Why do you think that getting more than 6 into combat is hard? Getting 12 into combat is easy! They're fast, and they fly, and most enemy units are big and/or stretched out by necessity. Alternatively, just charge two enemy units to maximise your attacks. It's really not that big a deal.
Personally I did all my maths when the book came out assuming that the Ripper CA would get nerfed, and to be honest, without even using the chief. I didn't like adding the extra drop. And I still think that Rippers are better than Terradons if they're your main combat units, unless your plan is specifically to alpha things off the board with rocks (which is legit also). Terradons are also better when you're just splashing them for speed / hero sniping / filling out a Shadowstrike.