LOL, I hear you! I have spent/wasted many hours playing around with something (usually in the fpe's), trying to get it to work simply because I didn't know it wasn't working yet! I mean, my assumption has always been if it's there, it must be working, right? Not so! So many of those properties in the fpe are leftover from Classic's fpe's and are currently still hard-coded in the engine. It never hurts to ask here, of course, but there's not any guarantees that anybody will read you post! So much valuable information gets lost in a forum of this type simply because it's unorganized and growing every day. Search is weak at best. Like you said it would be nice to know what doesn't work yet but really the only thing we can know is what they tell us in the change logs and by looking at Lee's blog. Anymore, if I try something and it doesn't work after the first few tries, I just assume it's hard-coded and move on for now.
As for your sky and terrain reverting back to the defaults, are you actually saving your map? Like I said it did that to me with 1.007 but 1.0071 fixed it. You may want to ask over in the product chat thread or the bug reports. The powers that be may be able to take a look at your map and figure out what's wrong. Good Luck!
MAME Cab PC: i7 4770@3.4Ghz (passmark 9945), 12GB RAM, Win 8.1/64, GeForce GTX645 (passmark 1898); Shiny new laptop: i7 4800MQ@2.7Ghz (passmark 8586), 16GB RAM, Win 8.1/64, GeForce GTX870M (passmark 3598); Old laptop: i5@2.3Ghz, 8GB RAM, Win 7/64, Intel 3000 graphics