I have not investigated TSL dialogs yet, obviously.
LOL! I on the other hand don't know what was (and what wasn't) possible with the first game. I felt the modding force only with TSL.
But yes, you can add params (whole bunch of them) in dlg files which will be passed to scripts you're calling. I guess this makes usage of scripts more effecient since you can write more generic code. Unfortunately, so far you can only modify/add them with GFFEditor which is pain in the butt, especially with large dialogs.
Anyway, I eagerly await your next release.