I've been holding off on getting into Civ 6 modding until the tools are released, at the very least. One of the big reasons is that I've gotten so accustomed to being able to implement unique improvement and unit graphics to help shape the look of the game, I'm quite leery about getting into modding Civ 6 until I have some idea that it'll be able to support a similar level of graphics modding. Sure, a unit builder where one can swap helmets and weapons around is handy for historical modders, but it's going to be pretty useless for me to build a railgun-firing flying superfortress or flame-flinging wizards like I can do with Civ 5. Some of the improvement modding tools may at least be able to import models over, but I do still wonder how much the acclaimed wonder animations are going to be able to accept modded wonders -- what if you NEED a wonder animation to implement a wonder? The question of whether or not we'll be able to actually import and modify effects is another question, since that was a big handicap in Civ 5, and the lack of any sort of fantasy or sci-fi effects in the current version of Civ 6 may put a damper on anything other than historical mods if no effects can be imported.
There's also the question of what the Lua API will look like. As much as lots of modders got intimidated by Lua and are probably eager to just make XML-only mods, I've found that Lua offered a lot of flexibility for triggers and things. Want a building whose yields change depending on arbitrary environmental conditions? You probably can't do that with XML tables. Want to restrict unit production -- for example, only being able to build a certain unit if you have a certain wonder in your empire? Not sure you can do that with the XML tables either. Want to have a wonder spawn units randomly, or have a civ's UA do that? Again, probably can't do it only with XML. So I'll be curious to know what event handlers actually exist in the Civ 6 Lua API, particularly considering how several were missing in Civ 5 that had to get modded in via certain DLL mods.
Still, I suppose at this point some things should be apparently from examination of the XML tables. I'd be curious to know if they actually managed to provide unified yields, and whether or not buildings can actually modify everything -- the fact that Civ 5 buildings can't modify improvements is a source of great irritation to me, but since they actually did provide that functionality in Beyond Earth I'm hoping they learned their lesson and made buildings, policies, and so on flexible enough to modify most game elements.
