Is there a slam dunk answer to the optimal amount you should dip into alchemy and crafting for a hardcore kill-as-many-people-as-possible combat character? Can you ever get weapons/armor with the perk type shit (e.g. masterwork) without bothering with crafting at all?
Are there some really "money" breakpoints for alchemy/crafting you can get that will help immediately, or do you need to focus on them?
Quote me in a reply so I don't have to browse through the thread 'cuz I don't want non-build spoilers.
A hardcore kill-as-many-people-as-possible character can just focus on combat skills, really. If you have solid combat attributes and high dodge, cs, and weapon skill, you will annihilate the opposition. You can buy fire potions, acid vials (destroys shields + armour), and poison with money from selling dead people's equipment. Crafting isn't strictly necessary, either; you can get reliable steel weapons and armour without too much trouble. If you're a blocker, the best armour is non craftable anyway, so ultimately you'd just be making your weapon once you hit Ganezzar.
I find alchemy and/or crafting to be required for hybrid characters, though. With a 4 str 6 dex character you can go ranged and alchemy, for example, and rely on high level fire, poison, bombs, splash acid, etc. Crafting will get you the best ranged weapons early on. That leaves plenty of stat points for other attributes, and you can make do with just 4 or 5 points in ranged. I guess you could go even lower dex and just use a lot of quicksilver to make +AP potions, because I just did an hybrid run and found at least 6+ quicksilver roots on the ground.
Yes, you can definitely get upgraded armour and weapons without any crafting. You can get it in Teron even, although the selection is limited. Try sneaking into the Blacksmith's home and unlocking his chest, or killing Sorab's friends as a Praetor. Or pay to let the merchant in the gates. In Maadoran, all characters have access to upgraded steel equipment, and there is also some higher level stuff, too. However, it can be difficult to get a lot of it, so unless you're Herakles you're going to need alchemy & crafting anyway.
Real breakpoints?
Well, I would say crafting isn't really groundbreaking until you get to steel. You can find some good bronze and iron stuff easily, but once you hit steel you can make some extremely powerful equipment; I think it's skill 6 or something. There's a lot of steel in the game, too, so it's not impossible to just roll around in upgraded steel imperial armour, helmet and have a giant fuckoff steel sword part-way through Maadoran. That's basically game breaking if you have halfway decent combat stats. There is some very powerful equipment you can get without crafting by this point, but your particular character might not have access to it; crafting is a guarantee.
As for alchemy, I'd say it's useful even at the lowest levels. As soon as you hit firewall and poison, you can start dominating. Given that you're usually outnumbered, it's very important to be able to funnel people with fire, and the damage output from poison is crucial. You'll want to sink more points in, though, because the poison becomes progressively more powerful (I think it maxes out at 9 damage a turn, which is huge), the fire lasts longer and does more contact damage, and you get thinks like large explosives/shrapnel bombs, burning acid that destroys shields and armour and does burning damage, +AP +ToHitChance potions, +Damage +DamageResistance potions, etc.