Turn based, or even tile based are hard, impossible, awkward, or unse un-friendly in a simple internet browser.
Sure, they could be done, but it would make the game only even playable to about 10 or so hardcore DF fans, and that will make it highly improbable to get more than 2 users on at a time.
Users could tolerate turn based OR tile based in an internet browser, but few could tolerate both.
Add to that the complexity of DF, or even a fraction of it, and you have a game that will die from inactivity.
Maybe I am wrong, but the average user will only tolerate so much...
A java based roguelike inspired tile MMO with a turn once each second would work, but HTML is too static.
Just curious, but how many browser based games have you ever played?
In my small(a few games currently being played) experience, users "like" a sense of security(a 99% chance of nothing too bad happening while they are gone, at least initially, and no requirement to rebuild from NOTHING afterwards) and often they also would like times where they can do nothing, allowing for other online activities, as well as times where they can do a lot quickly(such as just after logging on), but whatever happens, people like options, and the ability to only HAVE to play 5 minutes a day(or even take a break for a week) or play a whole 6 hours in a day if they want, with few consequences of their schedules either way.
Bottom line:
-non DF obsessed users need:
--secuirity
--wide range of time lengths to play
--a second chance when they "die" so they don't los everything
-An internet browser is bad for roguelike turn based stuff
-(but okay for resource(energy,food,other) based systems
But most importantly, you can continue with this any way and still get somewhere, but with fewer satisfied users.