If you're gonna buy a boost and the xpac, just to play some passable story and have a sense of progression for 30 hours, you might as well just buy an actual RPG for the same price.
Well, I have to reiterate that to me,
GW2's main draw is its sense of adventure. Constantly going to new fantasy maps and traversing them in unique ways. Also engaging events and combat. I'm hard pressed to think of other games that provide that experience. Maybe Zelda, but it doesn't provide anywhere near the same amount of content.
How important is party composition and playing off of each other classes?
Hardly important most of the time. If you're playing the story or open world, you can role with whatever build so long as it is not a support build. Good luck trying to kill anything as a healer Druid.
How has combat changed since vanilla GW2?
A new mechanic called the Defiance Bar (aka the Break Bar) was added to champions and bosses. Such mobs are initially invulnerable to crowd control. Applying crowd control gradually depletes their break bar. Once fully depleted, the mob becomes vulnerable to all CCs for several seconds before regenning their break bar to full. Previously, CC was near useless against champions and bosses because diminishing returns made them immune to CC forever really fast.
Are elite specs mandatory to perform well in endgame
Define "endgame". If you mean running fractals (time attack dungeons, aka mythic+ from WoW) then yes there are certain builds that are favored. Otherwise you can just roll with whatever. Some core vanilla classes have been neglected and aren't as good as the elite specs but you can still do all story and overworld content with them. Some core classes like Ranger are still just as good as their elite specs.
would I be forced to use the weapon associated with the spec?
No.
How is the leveling/Main story experience?
As aforementioned, levelling is awful. Most existing players just use their level boosts they accumulate from log in rewards and birthdays to boost a new character straight to 80.
The first 1/3rd of GW2's storyline is disjointed. The vanilla game's storyline has you adventure with Destiny's Edge and fight a zombie dragon. However, Destiny's Edge was voiced by A-list voice actors such as Steve Blum, Troy Baker, Felicia Day, Kari Wahlgren, etc. Probably more expensive to retain than Arena Net wanted, so in season 1 Destiny's Edge was written out of the story (except for Rytlock, who was a breakout character) and replaced with a brand new cast of characters (that people genereally don't like as much as Destiny's Edge). Unfortunately, you cannot play season 1, so if you finish the vanilla story and jump into the next playable segment (season 2 or HoT), then you suddenly go from adventuring with characters you knew and cared about to adventuring with people you know nothing about. The general sentiment of the fandom is that Rox, Majory, Kasmeer, Eir's son, and Taimi aren't as likeable as their predecessors. You gradually pick up more about them as you go on, but I didn't care about them as much as Destiny's Edge. It's pretty telling when the big finale of the story happened at the end of season 4, only the Destiny's Edge characters were there, with the sole new character being Aurene. Canach is okay in my book, though.
The first 1/3rd of the season 1 story is being added back into the game next week.
Another problem with S2's storyline is that you weren't going to many new places. You had 8 episodes (2-3 hours each) set in just two maps. Also, the player character isn't voiced in S2.
Main story starts getting pretty decent in the HoT expansion and season 3. You go to a new place in every episode, so even if you don't like the characters very much it feels like you're going on a globe trotting journey through a fantasy world. You also start getting some cool setpieces. Also the villains start getting a little more interesting than "rawr dragon". Also, Aurene is introduced and is pretty okay. I'm almost tempted to say I like her. A little. The player character is also voiced again.
Is there more party content before reaching endgame?
There is hardly any mandatory content you have to do with other players to beat the story. If you want to play with others, then you can do events out on the world (but you won't really make friends with anyone) or do PvP. Once you reach level 80 you can do fractals and raids (join a discord for the latter).
Is 80 still the level cap?
Yes.
re the expansion's zones more dangerous and would it require you to go with a party?
You can solo almost all overworld content in any expansion. Only stuff you need more players for are the meta event finales where you need multiple players in different locations across the map (ie, the Tarir meta event, Dragon's Stand, etc).
