I think Multi-tiered arenas are awesome - they add a lot more excitement to a fight due to the threat of being kicked through a wall or into the sea. This feature makes MKD stand out from other fighting games such as Soul Caliber.

Needs to stay! And improve also. It is too DOA like, and there aer more possibilties in them than anyone could know. Also, there should be a multi leveled fight possibilty, like in BIO F.R.E.A.K.S. (also a Midway game) that would allow fighters to have an advantage of being at a position higher than the other.
Vertical and horizontal multi-level stages. How about a japanese fortress interior with paper walls? You cuold punch your opponent through them to get to another section of the arena.
Deathtraps, more deathtraps!!! Also, bring back the statuary garden from MK1 and allow the others to push a statue on the enemy. How awesome that would be?

The multi-leveled stages in Deception are not very good honestly. They aren't very creative and the actual animations are stiff (look at the landings, they don't look right how your character ALWAYS lands the same way) and sometimes glitchy. In one shot you'll see your character fall towards an overhang or something and then in the next shot they land perfectly in a spot they weren't falling towards. There also isn't a true wall system in this game which is what it really needs to accompany the breakable walls of the multi-leveled arenas. Not only that but all of the arenas are still just completely flat slabs of earth, there are no height differences in the terrain.
The levels are very simplistic in their actual design, but I will admit they are a BIG step-up from DA and their "magical" green energy barriers. The levels they implemented are sloppy, but I suppose they do get the job done. They need a LOT of work though.

Death Traps I know you can turn them off , but still I rather have a invisable wall that does low amount of damage than something that results in a defeat, but because I was in the wrong spot on the arena. I want to fight till the best man wins.
Multi tiered Pretty good idea. They are sort of like MK3 multi tiered levels. Fun to pull off and not important , but
Konquest - Not as insightfull as MK: DA Konquest. Deception's Konquest is very borning. It adds little to the MK storyline. The most of the stuff you do in Konquestit is too much of a hassle .
Chess- Good idea, but I'd rather have more fighting modes
Puzzle - Nice idea , but not neccsary. Not in joyable beyond for long.
more later

i think the multi leveled stages are far too easy to access. what i mean is, a hit that normally will only do a small amount of damage will all of a sudden knock u through a wall if your in the wrong place. same thing with the death traps. u should only be able to knock someone into them with a hit that would knock the player of their feet. they are a good idea though, and should be kept for future games.
to sum it up i like everything in this game, but it could all be improved.