I don’t think you should ever skip an elite. They tend to be easier than many normal fights unless it is a specific elite that hard-counters your team.
Here’s the thing about Ability Orbs and characters - I think one of the reasons I’ve had so much success with Paladin/Warlock/Bloodmage + Assassin + Fiend is that they have a very good Ability Orb synergy. Let me explain.
The Paladin doesn’t need to DPS in this composition, you can end the run with his passive never upgraded just fine. (I’ll add that I have won with him DPSing as well, but he can tank Corruption 1-19 just fine). So this just leaves him needing Red Orbs.
Warlock doesn’t need his passive until the 3rd floor where you get Fiend. Even then, I’d say one more item upgrade is often more beneficial. His active ability needs to be the first one you level so his heal always hits both the Paladin and Bloodmage.
Like how Warlock desperately needs 1 level in his active ability, Bloodmage needs to level his passive right away to have any value. In this composition his Active is situationally worth upgrading. It is a nice DPS increase.
Assassin just needs passive upgrades as his Active is merely a very meh DPS increase, and Fiend needs none at all to do what he needs to do. So this composition really lets you have a lot of upgraded items for the final battle since you can safely sell some orbs without losing anything.
Heroes like Berserker who basically need all 4 ability upgrades to function lose a lot of points in my book for this reason.