The elemental temples always use the same layout, with the same monster formations, and that makes them a bit unexciting. You can pretty much use the same approach and strategy on each playthrough (e.g. avoid the fire elemental rooms in ToEF by digging past them). If each temple had a number of possible layouts similar to how there's different shapes of vaults, that would bring a bit more strategic depth and unpredictability into clearing them. The number wouldn't need to be huge, like 3 layouts for each temple would be enough, and some of the layouts could potentially be used by more than one temple (though not in the same playthrough). This would also make scrolls of mapping and wands of monster detection that much more useful.

There could be some slightly mazelike layouts with 'close quarters' combat. Layouts with long open lanes favoring spellcasters. Open and sparse layouts. Layouts where it's easier to get surrounded from the sides. Even layouts with a hidden treasure stash.

This would probably mean a big workload though, so it's not a short term goal. I'll set it priority 8.