So, DiRT Rally is apparently a thing. It just hit Steam Early Access minutes ago with zero buildup or fanfare from Codemasters (...they announced it on Twitter about 15 minutes after it was already available). You can check it out here: http://store.steampowered.com/app/310560
With no info being out there and having not played it yet, it looks like this does return to a tighter focus on simulation rally racing (the description specifically mentions FIA World Rallycross Championship branding). It seems as though it's relatively full featured at this point, but that Codemasters will be adding content throughout the rest of 2015 while it's in early access.