Increase EXP from side quests once main quest complete or max lvl a class

[Jojoya]

yet no one does them because most of them are pointless

People do them because they enjoy getting the additional lore/stories for the zone.

Not everything needs to revolve around leveling/power progression.\

fair point but you could also have the potential to make people more interested in the lore with them, I do think there should have a bit more reward in doing them other than just the lore.

If players aren't already taking an interest in the lore from doing MSQ, adding more XP to side quests isn't going to change their interest in the lore.