The Tavern

Currently the orb lacks meaning and orb run is tedious.

1. Idea: Orb as a god-making thing, that is, if player manages to escape with orb, all existing pantheon will be destroyed and the player becomes a great god himself.
2. Mechanics: Once orb is taken, player loses his deity and gets wrath of all gods until he gets out or die.

You can't create meaning by telling a silly story. It does not matter "what happens" after you win the game. Strictly speaking, nothing happens, the game is just over.

The orbrun is indeed bad, but you should actually see what the simultaneous wrath of all or even several gods looks like before proposing it as a mandatory game mechanic.

Idea: orb as a delicious sweet. It is like one of those German chocolates, or maybe a Swedish one, but of course the ingame flavor is it was made in Pandemonium.
Mechanics: instead of the orbrun, your character must (e)at the orb after picking it up in order to win the game. Has a side benefit of expanding upon the food system, one of crawl's many enticing gameplay features. Mummies would have to (a)bsorb the chocolate into their bandages over the course of several turns.

Compared to other roguelike dungeon crawls, I think the orb run is pretty good. Especially my first time, I was in a "HOLYSHITHOLYSHIT" sweat the whole way.

Having seen it a bunch of times, it's gotten old (though can still kill me).

I'd hope that it's retained but as one of N possible endgames, chosen at random.

Can't it be tested in wizard?

Crawl in its current state aligns well with real life: all journeys come to an end regardless of personal success, leaving behind statistical records that do little to communicate the experience of the personal struggles we faced along the way. If we believe the gods must take retribution against individuals who have amassed great power, I think we should implement that in our own world before we do so in Crawl.