So yea, long story short I'm playing as an archer and joined the militia. I was under the impression that any playstyle can join any faction. However, the guy from docks can't train my dexterity after 30 and I haven't found another trainer. I took a peek at a walkthrough on IGN and it seems like the only trainer for dexterity that goes past 30 is part of Mercenaries? Is that really the case?

I'm playing Gothic 2 with Classic mod, not NOTR.

Edit: Also, first time playign this, so keep spoilers to minimum, please!

Indeed, this turned out to be the solution, so thanks for that. Now I've ran into the next problem; Ruga won't teach past 60. Are there any other trainers for militia players past 60 in Chapter 1?

In chapter 1 there is another possible teacher, but it depends on your choice about some criminals...

Otherwise you have to wait for the beginning of the 3rd chapter to find a teacher up to 100.

Oh... oh... well, at least I got a nice sword. Which I can't wield because I'm 5 dex points short. But is there gonna be someone in chapter 2 that can teach something between 60-90? I'm an archer so I'd imagine it's gonna be torturous to make it all the way to chapter 3 with 60 dex.

Unfortunately, in chapter 2 there isn't a new teacher for dexterity. Maybe you should have waited before joining the militia to learn dexterity up to 90 from Torlof.

These are the only aviable options:
SPOILER
- become a member of the thieves guild and learn from Cassia up to 90;
- drink an Elixir of Dexterity if you had already find it (+ 5 dexterity);
- eat Goblin Berries (+1 dexterity)
Players usually keep the elixirs / the plant with bonus and use them after reaching the max level, but it's your choice of course!

Ah, god dammit. See, this is the downside of no hand-holding. While I like it that the game doesn't tell me what to do and when, there are moments like this where I simply could not have predicted this. Unfortunately, my pre-militia save would take me several hours back. Guess I'll have to consider using it if even those boosts don't seem to help enough. Luckily doing the mercenary quests will be new content, so I don't have to go through hours of stuff I've already done.

But thanks for your help!