Napkin math to me suggests that something the party had trouble fighting is worth more experience than something the party didn't have trouble fighting. If you have a mountain path full of monsters and the characters need to get to the top, and they just teleport up there, do you give them the exp for bypassing them? No. It's Challenge Rating. Challenge. If there's no challenge, there's no challenge rating, ergo, no XP.
I base levelling up on 4 difficult encounters per level, with some additional requirements on top of that for roleplaying, so maybe something like a 22:22:22:22:12 split for requiring to level. Just going into a dungeon and fighting 4 difficult encounters (and making hard work of it) will get more XP than one. It helps prevent some people from stealing the show with CharOp tricks as well if they don't get any XP, and it becomes self policing within the party.