Alchemist, you max magic, get con and willpower to a comfortable level, and then max cunning, with whatever ends up being left after all that going into con. I stop investing into wil when it hits about forty or so, con around the same point. Then I max cunning, for the crit boost. Then whatever's left goes into con. Alchies don't actually need that much mana, so they can skimp a bit on willpower, but con keeps them from splatting after the golem does and cunning is another damage multiplier (and a potential mana source, if you've got a mana-on-crit weapon; one of the better artifact staves provide that, so...).
Wardens are more complicated. Their primary stats are definitely willpower and magic, but depending on things you can skimp on magic a bit, using quantum feed and a high willpower to take up the slack. After those, though, you invest according to your build.
A melee heavy TW that's not going dual-daggers will invest more into strength than dex, and may or may not invest into magic beyond the minimum. It's up to them whether they use strength of purpose to pump their strength to ludicrous levels (hitting tremendously hard with the main hand) or to allow them to skimp a bit of strength (with the spare going into... whatever. Magic, dex, con... possibly cun, with a crit build.). A strength-centered TW will probably want to offhand a mindstar these days, and just not bother with dex once you've got enough for flurry or whatev'... at most enough to qualify for the fifth tier bows, and a lot of that can be supplemented with kit.
A dual-dagger TW will go into dex, and probably supplement that with bow use (since they're already using a dex-prime weapon and bows secondary scaling stat gets boosted by SoP). They may or may not invest in dex beyond the minimum needed to wear voratun daggers (48, iirc) and then boost something else (again, magic, con, or cun; the third helps with dagger damage a bit, on top of the crit).
Bow-warden will go dex, obviously, with spare points (after willpower and dex is maxed and magic is as high as you feel like going) going into strength, to boost bow damage, or magic, to improve the effectiveness of various talents. I'd probably emphasize magic with whatever's left over over strength, though -- bows do plenty of damage without much help, heh, and magic makes a lot of a warden's defining stuff better.
Caster-heavy warden will go about evenly into dex and strength, with emphasis depending on weapon choice (dual-dagger, staff, or other) after willpower and magic is maxed and con is comfortable.
Early game, I max willpower and stick the rest into whatever I need to hit talent or kit requirements. Mid, I tend to focus in on the latter part of that, hitting kit stat breakpoints and making sure I qualify for all the talents I plan on using. Late game, I tend to focus in on magic if it's not already maxed -- I find that my wardens do best when their utility skills are at their most powerful, and most of them scale off spellpower. Once will and magic are maxed, the rest go into whatever I'm emphasizing; probably dex if I'm not going heavy into non-dex scaling weapons, since it boosts both daggers (which you'll probably end up offhanding in the late game just for the spellpower boost on a couple of artifact daggers) and bows. There's a good chance I go cun, though, especially if I'm playing a shalore -- spellcrit helps wardens too, if not as much as a dedicated caster class, and the physcrit benefits stuff like flurry, too. It's pretty easy to get a crit chance in the mid-twenties (just about guaranteeing one or two crates per flurry) in the late game without really trying.
Emphasis into con depends a
lot on how comfortable you are with the game... I find myself skimping on it considerably these days (using kit to qualify for thick skin), but some investment in it will definitely let your play less carefully, and is good for learning the game a bit better. More wiggle room for running into stuff you've never run into before and you're not quite sure how to deal with. You can never really go
wrong with con, though, if you've got what you need elsewhere and aren't quite sure what to do with the leftovers. I just prefer to embody the "make the other poor bastard die for their country" philosophy
If the enemy's dead before they can hurt you, you're in good shape, huhuhu.