Since the combat is turn based I very like to see Skills where tactical/strategical planning is often the best way to win a battle in a more effortless way !
So aimless actions will not rewarded well winning a battle ... so the game can't never be a "no brain clic feast" !
I really hope you can find/buy in the world of Rivellon Skillbooks like in DD, but not only books for Spells, also all kind of skills can be found well hidden in the game world.
1 point per level up and each 5 levels 1 point extra is fine (DD) !
Funny secret ways also I really love it, like in DD it was fun to discover reading some books you learn a point in Trader's Tongue(DD), wearing all pieces of the Dragon Armor you learn a skill, etc etc ... nice & great ways to gain an extra skillpoint !
And I'm sure many other ways are possible !!
And of course an OPEN skill tree I love most ! (like DD, DKS)