Some people like the "do it to learn it" system where if you mine, you get better at mining, if you shoot a crossbow you get better at crossbows.
Others like me prefer the current "everything gets you xp, spend it on what you like" system.
I thought about a hybrid version that could maybe appeal to both sides. When you get XP it's split into 3 amongst attribute, skill and general xp.
For example, you use a crossbow to shoot a zombie worth 600xp - 200 xp goes into Agility, 200 xp goes into crossbows and 200 xp goes into a general xp pool. Stats and skills raise when you reach certain xp levels and the general xp pool can be spent on any skills to raise them, either by granting points at certain levels or by allowing you to directly spend the xp.
This would reduce the grindy nature of the "do it to learn it" system (remember the days of levelling up by crafting hundreds of stone axes?), while still giving a mostly natural progression in whichever skills you use the most.
