So far, in the early game, I don't have a problem of "too much XP". For me, the issue is that I need to do every single quest and kill every single enemy to scrape up enough XP to get enough to match the enemy levels. I think the only quest I haven't done is the Eiglander one, and the crowdwarmer one, which didn't even grant XP in the last patch, if I recall. The rest require visiting different areas. Matching the enemy level seems pretty important to survive and to be able to hit things reliably.
If you want to be level 3 when you pick up the companions, AND still see the henchmen's dialogue for the various quests and story checks, it's possible, but requires careful planning (and a bit of luck).
There are only a few level 3 and level 4 enemies. The enemy levels go up pretty quickly, and there doesn't seem to be a lot of room to reach level 5 before taking on groups of level 5 enemies. I don't know if there really is much optional content.
Of course, I am on Hard difficulty.
This is probably better than it was a few patches ago, when after reaching level 5, I skipped large chunks of content and still out-levelled the final boss of the beta, but I'm not quite sure we're there yet.
