I haven't heard about the Cotton Belt project going to Wylie or Murphy.
The D2 subway project is projected to only have five stops because it's not designed to be a standalone subway project. It's a realignment of probably the Green and Orange lines in order to alleviate congestion in the existing corridor downtown. As it is, ALL trains are going on that same stretch through the Central Business District. If anything goes wrong in that stretch from Northwest to Southeast junctions, it impacts the entire system. No bueno.
I'm not privy to that kind of information about the Texas High Speed Rail project, and haven't heard anything about another rail project between Dallas and Fort Worth. Seems kind of redundant, honestly.