I too think that the item level should be increased, as of now you can barely fill half of the nodes. Don’t get me wrong, unlocking everything like in D3 is horrible idea, however being able to get only around 50% of the potential of a skill feels underwhelming, which is one of main addictive components of RPG games.
So I agree that we should increase the cap and make the last several nodes really hard to unlock.
In terms of + Skill Levels from items, I think that Diablo 2 did it the best, in a way that it was not as a rare thing to come-by. If we have only one or two items that give you this suffix then we will be locked around those items, however if it’s a kinda normal stat for an item with item level of X+ and there is hard cap how much + Skill level we can get from items it will be good.
For example Hammerthrow can benefit from +3 Skill points from item and this being a hard cap,.