Hello, I have played the game for a bit now(about to finish my 4th or 5th dungeon) and come to wonder, how exactly weapon proficiency works, especially since I might have focused on the "wrong" weapon...

I got 4 points in axe but only come across good swords and spears it seems. Does anyone have an idea if I am better of with a 1d8 axe with 4 points in hacking or a 2d8 great sword with 1 point in slashing?
Is weapon proficiency just +1 damage per point or per two points or something else?

I'm not exactly sure how proficiency works. It does seem to make you do more damage.

You will come across a few good hacking weapons throughout the course of the game. The best of these is a hammer that does a fair amount of damage and which will actually end up being the best weapon available to any player up until you get a really great sword late in the game. So hacking weapons aren't a bad choice, since you will have that hammer for quite a while and when you do it will be the best weapon available to you (Steelripper excluding).