these are by means new/revolutionary ideas but I'd like to give my take on them and possibly have others chime in if they are interested in the same.

1.) more unique maps

there are a few maps that are set in stone (ie. you don't have variations on them based on theme/element), namely the boss levels (firestorm citadel and whatever the jelly kings lair is called), the graveyard (right?), and I think there is at least one other special one but i don't know the name. i think that it would be cool for there to be at least one level per strata type that is perhaps rare, but completely unique. no different flavors for the varying elements, just a a solid map related to the strata type, perhaps with some unique mechanisms or challenges on it.

in the same vein...

2.) (more?) levels with specific objectives

I don't really have too many ideas in this department, but it would be nice if there were some puzzles / mechanics that were required to get through a level beyond hitting /placing an object on one or more switches or clearing all enemies in a room.

A few quick ideas:
a.) an undead mission with multiple less aggressive phantoms that have to be coralled into a holy circle to be cleansed/exorcised. holy symbol could be in the center of the map (with the down elevator located above and the previous elevator below, or vice versa), and some branches off to each side where the phantoms reside. i haven't been to vanadukes lair yet, I believe there may be a mechanic like that down there with those sprites? so something like that but.. not there.

b.) rescue mission where you need to unlock (one or more) [NPCs / those birds / something] from behind a series of locked gates using the standard gold keys. perhaps a mini-boss has the one (or the only) key you need to unlock them. like a prison level where you have to free the hostages before descending. again, might be like something down in vanadukes area but I don't know that from experience yet.

c.) something where you have to escort an NPC through a linear gauntlet of traps, failure to keep them alive means starting the level back at the beginning (but maybe the enemies don't respawn, just the traps)

again, nothing I put much though into this so you can razz the ideas if you want, but i think theres a need for some variety like this..

3.) more environmental hazards / objects to interact with

again, winging some examples:

- environmental objects that spit fire/hot steam/ice mist/whatever that are not underneath you (the grates/spikes). something like a gun puppy but not
something you can destroy, or would aim at you. just another hazard you must time yourself with when passing. some might be used to block paths and you have to hit the right switch to disable.

- bridges that drop / expand when you hit a switch or physically attack it -- we need some more mechanics to block progress that aren't just gates. i get that its just a new shirt on the same old mechanism, but when you boil down game mechanics, thats what a lot of it is. so at least trick us into thinking we're doing something different :)

- teleport squares? i imagine there might be problems with this, especially when considering how enemies would interact with it

- objects that require coordination with teammates -- as in zelda, sometimes you have to hit switches at the same time to get it to work. so a series of switches (perhaps spread apart so you cant see your teammates) so you have to count down before hitting it, and opening a door. you have to time it right or it wont work. the caveat here is that this has to be able to work if a player is soloing, so I'm not sure what concession we could have there. maybe the number of switches that has to be hit at once depends on how many active players are in the dungeon.

- etc etc.

and there are some other things i'd like to see, but i realize they will come into fruition naturally over time:
- new enemies in each class
- new bosses
- new levels per strata type (with elemental variations)
- 1 or more new strata types (I'd like to see something aquatic, and maybe something more like a cavern)

please add your own ideas!