its really not about treaty vs other game types/which is better. id like to play 1 or 2 treaty games a week for the something different u get in it, but i wouldnt because
-30/40mins building eco is a waste of time
-it has 0 balance
so dm w/small nr time would eliminate those 2 issues.
in response to a couple points:
"also games would be even less balanced, IMO there is less balance in DM than there is in treaty."
i can only speak for nilla but other than german, its pretty well balanced, every civ having + and _'s. a big factor in making treaty games no fun / no skill is the walls, u cant do anything b/c of them other than have huge cannon spamming wars. you can see game stats of treaty/nr gams where a player has made like 200+ cannons. somethings pretty wrong with a game type where this happens.
if you made it NR 3 mins and , say, no walls as a rule, you would have the time to get your eco going and be able to build all over your half and prime yourself for the fighting (as in treaty), except you remove the elements of treaty which make it a skill-less game type: walls,huge stockpiles of res,cards like fur trade.
instead of having to slowly pound through layers of walls with tonns of cannons, ridiculous stockpiles of res and op units you would have to raid (with exposed ecos, lol,imagine that treaty players :P), micro (you couldnt afford to spam cuirs, eg, with their frail early game dm eco) and macro at the same time. essentially dm-like gameplay but modified somewhat in the style of a treaty game.
and you would be able to use a much larger variety of civs, and not 1/2 each game
but you should at least try it i couldnt imagine going back to the days of 1 game taking at least 1hr30mins, some 2 1/2, some even 3.