alternatively you can also have a system where there you can only reach a certain level in an act for instance (if they still exist) even though there is a lot more exp. Like you do the main story and only 5 out of 10 side quests to reach the cap in that act, which would be level 6. So you dont feel like you have to do every single thing, since you cannot suprass that level.
Of course, you still have this feeling of needing to do those 5 side quests. As well as the problem of trying to maintain a lure for people to continue doing things within the act once they hit the "Experience cap" for it.
Given that the standard motivation for many to do side content, is the experience reward. If they stop getting it, then they stop caring to do it (And/or it feels unrewarding to do)
Hence why if experience is removed entirely, you'd need to ensure there is good enough draw to make people want to interact with stuff. Same would apply here, you'd need to provide compelling reason for people to continue doing stuff once experience stops (Of course, without going too far and making the rewards so good that people feel forced to do things to obtain them, effectively going right back to where we started with experience and the need to obtain all of it...)
