[Skills all wrong in RPGs?]

I think that the increase should be small around 2-10% increase for every level and that would be in selected areas, then let objects do the rest with bonuses, so it rewards exploration. 

[How much stronger should you become when levelling up?]

In my opinion the character should get slight bonuses like 2-10% and let equipment and other things effect more so if you find some really amazing gear then you have a good character but if you somehow lose it your back at square 1 with only a few advantages. 

[Is project eternity the best managed kickstarter game?]

In terms of what I know and as far as I have researched I do think P:E is in a very good area compared to others including double fine and planetary Annihilation, but keep in mind this is our side of the story so we should take this with a grain of salt.