I know that an essential aspect of this game is, that we can only select a few skills out of many for our character. This is a good system, because it makes the possible ways of building a character very varied, but at the same time, it requires us to start from scratch with a new character, if we want to try out something different, or even if we have made an unwise choice with just one skill.
I suggest that it becomes possible to unlock all skills with one character, but that we can still use only 7 of them at a time. We should of course not be able to do this without restrictions, so here are some possible options:
1. We can visit a specific location, where we are allowed to select our chosen set of skills. In all other locations, the skills are locked and can't be changed.
2. We are allowed to change our set of skills once a day (within a 24 hour period).
3. We are allowed to swap one of our skills with another, perhaps every hour or even only once a day.
I think this would make it more fun to play around with various skill combinations, and it will still take a very long time to level up all skills for those who want to have them all, as they only get XP when we use them.