I played some Vermintide 1 - have everything completed on Cataclysm, most reds aquired etc. so I suppose I could be called a 'veteran'. I got into the VT2 beta two 'phases' ago and managed to get some playtime, so:
- In my opinion VT1 is one of those games that seem to have simplistic mechanics, but prove to be much deeper the longer you play and the harder difficulties you try. Despite not much changing between those difficulties, you have to change your tactics to a degree when switching from Hard to Nightmare, and then change them completely from Nightmare to Cata (unless you intend to be just carried by a more experienced team - sometimes that works). So while VT2 seems similar, some of the finer details have changed, and gameplay implications seem to be rather notable - weapon combos have been modified, damage system reworked etc. - that people who routinely completed Cata in the first game had considerable problems on Hard in VT2 and had to spend some time to adjust (which is a very good thing, new challenges and all that). But I agree that the core is basically the same: the same way to attack, dodge etc. - it just feels either a bit better (melee weapons), or SO MUCH BETTER (shooting with non-hitscan weapons - archery is way more efficient and consistent right now, without making it feel broken).
- Loot system is indeed better, if only for the fact (that I don't think you've mentioned) that you can now decide which character will get all the rewards, i.e. the character opening the reward box is the one getting ALL THREE DROPS (trinkets and resources are still universal, of course, but you are sure to only get weapons your selected character can use - if not always the currently selected career, since some of them have their unique weapons - like the longbow for forest hobo Kruber, and crossbow for dork elf Kerillian). Other than that nice addition, for all intents and purposes the only difference between the new and the old system is that you get three rewards instead of one (and no dice rolling). No lootbox mechanics (despite crappy presentation which does bring negative connotations and should be changed).
- Crafting has been completely reworked. Can't say if for the better. You seem to have a bit less control over the traits/properties than in VT1, which might be irritating in the long run for min-maxers.
- The game is somewhat loot/level based, which wasn't the case in VT1 - at least not to such a degree. In VT1 as long as you had a healing trait on a melee weapon, you were basically set. Other stuff could help, but wasn't *essential*. But here they introduced the concept of Power, which seems to scale damage done to enemies and is averaged from all your equipment AND your level (so if you have a weapon with weak-ish Power, but stack up trinkets with high levels, it will still increase the effective damage - well, as long as it passes the threshold). Someone calculated that there might be as much as 72% damage difference between a new character and one that reached level cap (30) with all the best possible gear. Which isn't that far from the difference some weapons had in VT1 between their white and orange versions, but still might rub some people the wrong way. I am not a fan of this system, but at least the cap is low so you reach the max damage values relatively quickly and if the values are balanced for the highest difficulties, I won't mind. It also has a side benefit of 'kickstarting' your other characters, since now all level up separately, but you can just give your lvl1 chars your Power 150 trinkets, and boost their initial efficiency.
- I wouldn't say that characters are gimped, rather the opposite. Hordes are way bigger and once I had been attacked by as much as four globadiers in the span of 30 seconds or so - so specials are also tuned up, although with all the new additions you barely ever see them repeating like that. The thing is that now you have way more 'effects' than before. In VT1 you were limited to up to 3 weapon traits (per weapon, so technically 6, but you couldn't use them both at the same time), and 3 trinket traits. That's it. Now each career has a passive ability, which grants 2-4 effects. Most of them are situational like in the case of Shade: "Backstabs deal 50% damage / Critical backstabs instantly slay human-sized enemies", or "Killed specials drop some ammo / quicker reload speed / no damage falloff / 2x ammo" for Veteran Ranger. Usually they're somewhat interesting and suggest what kind of playstyle would be best for a given career. Passives also include auras, like bonus stamina regen aura from elven Handmaiden. Then there are actives on various cooldowns (ranging from 40s to 2min from what I've seen so far), that can change a given situation considerably. They either turn you invisible, give you a charge/dash/teleport ability, stagger all enemies in range and give some other small bonus (a bit of temporary HP, bonus crit chance etc.). Aaaaand then there is the talent 'tree' - unique for each career. This is the one thing that's completely lvl-locked. It's divided into five rows of three talents each, you unlock each row every five levels (first at lvl5, the last at lvl25), and then pick one talent from every row. The first two are somewhat generic and some of them are shared between careers and characters - like +5% attack or movement speed/dodge distance, +40% ammo, +30% more healing from healing items etc. The third row always enhances your passive, so for example it can either make Shade's backstabs deal +100% damage, or grant 1 bolt or arrow etc. The fourth gives a healing ability like bloodlust or regrowth (the third -new- one gives a lot of HP back the moment you kill a monster enemy, like the ogre), but they've been heavily nerfed. Now they only give white/temporary HP, instead of normal green. Aaaaand the fifth improves the active ability (granting healing while invisible, or stopping bleeding when you use your AoE buffing shout - most characters also have a generic one that grants 30% cooldown reduction).
And then there are weapon properties and traits. Each weapon can now have only one trait, which is a non-random major effect, and up to two 'properties', which give random +% to a given characteristic (movement/attack speed, crit chance/power, extra damage on chaos/skaven/berserkers/monsters/armoured etc.). So all those things combined: passives, actives, tallents, traits, and properties - make for much more customisation and improve the ability to deal with all the new enemies and larger hordes. Which is nice - the game got way harder but it also gave you more tools to deal with the new challenges.
- Regular attacks stop being the only useful thing above normal difficulty, although to what extent depends largery on a weapon. On Nightmare you usually try to use as many charged as possible in the initial stages of the horde, but switch to normal when you want to focus on one enemy (or make a normal+charged combo to have two powerful single target strikes). There is some nuance but of course it's not very visible on the difficulty that has enemies dying from even the lightest strikes. It's like the balance between Swiftbow and Longbow/Handgun in VT1 - on normal even something as weak as swiftbow one shots almost every enemy, but on cataclysm you'd need around 10 shots to down a special, but only 1-2 shots from something like a longbow/handgun.
- I do agree that some weapons are way more 'niche' than others, especially the ones from VT1. Halberd, being a new weapon, is way more flexible and just plain fun to use than something like a 2h sword (from what I've seen so far. The same goes for elven weapons (new 2h elven sword, and the spear). Some of the old weapons were changed a bit and their stiking patterns improved, but I haven't tried all of them, so don't know how fun and effective they are now.
- Ranged balance is all over the place right now. Ranged careers of Kerillian and -especially- Victor as waaaay too OP right now, with Victor having a self buffing crit build that makes him both the most survivable (crits heal) and damaging (crits buff damage and crits) character. While Barding and Kruber feel a bit underwhelming, but at least they can still spam the shots with their 2x ammo.
So all in all I'd say it's a big improvement over the first with two caveats:
1. The power system needs to be explained better, or actually explained at all (there's supposed to be a proper tutorial written on it by launch, but so far we had to rely on numbercrunchers with too much time on their hands) and it might make the first hours of gameplay too reliant on loot and stats instead of teh skillz (but at least the level cap is low, so in the worst case scenario it'll be a bit like Guild Wars 1).
2. There are so many new elements to balance, that the game is -shall we say- not well balanced at the moment. Since this is a beta, damage and talent values tend to fluctuate A LOT, so maybe they'll make it better by launch. Either way they'll have to release balancing patches periodically to adress stuff like 'Saltzpyre crit build' etc. In VT1 they'd release a major balance overhaul every two monts and to be fair, they were usually spot on on most of the changes, so I guess I'm somewhat hopeful.
In short, game is gud.