I'm not familiar with dominion, but I do like roguelikes a lot, sounds like a fun mod
The patched Version of DO is pausable real-time you can pause and unpause the game using the space bar, this will allow you to check monster health and descriptions, browse your inventory and use certain items (i'm not sure what the restrictions are on that, I don't think you can change a full set of armor, but I might be wrong)
True turn based is not possible AFAIK
The quality of error reports for DO varies a lot depending on the error
. For some errors the game will pinpoint the file and the line that contains the error, in other cases it is not so obvious, but on average I would say it's quite good, and you can always post to the forums if you have an error you don't recognize. All datafile-errors I know of are announced when you first boot up your mod, before actual play begins, so after you made some changes you can easily check wether they will cause any new errors, without having to play half your module. This way you can also limit your search to the new changes you made. The mapgenerator program is also extremely usefull as a tool to spot any errors related to monster, item, or mapgeneration.