I'm also impatiently waiting for TFTD. Not exactly because of the game itself, since I never liked it much (it looked awful and was annoying in design), but because of some of its functionalities I'd like to see in OpenXCom (like making aliens able to have natural weapons AND normal weapons).
Perhaps there's been some confusion here, I think you underestimate what openxcom already can and does do. In fact I can't think of one thing that TFTDs engine has that's not currently fully functional in openxcom.
-AI can use melee weapons, both carried weapons and racial abilities. Ever heard of a chrysalid?
-Doors can be look-opened
-I think there's support for custom damage types from mods (like freeze, drill, or lightsaber if you want)
-Manufacture can create multiple items an hour
-can view stats from equip screen
-multistage missions are supported for cydonia, I think that's available to modders too.
-modders can add new mission types, I'm not sure if anyones done it yet.
-I never saw it in tftd but we have a TU bleed button in OXC now... I can't think of anything else and I've been playing TFTD all week.
OH, there's no under-water in OXC, and as such there might not be any functionality in place to run the second audio track. Or maybe it's in the code but not connected to anything in the ruleset. Also I don't know if OXC currently supports alternate color indexes - I'm pretty sure TFTD uses different color indexes for light levels underwater and above water.
