Crew 1 makes it very easy to have at least a few of them active each turn, and you only actually have to sacrifice three permanents to turn the entire fleet into flying creatures
Felonious Rage Monstrous Rage is likely still better, but boy would I rather have Felonious Rage in a Cacophony Scamp deck
This goes into any blue deck and isnt particularly demanding you cast it, and its good
The early prices bear this out, as people move sooner than they should, but its entirely possible that one or two of these dragons follows the Old Gnawbone path and just never gets cheap: Gnawbone is one end of the potential spectrum here, but the other end is this: My inclination is that while the Ancient Dragons are expensive mana-wise, they will generally be worth it on the board
Sleeved Booster Packs are also available
Thanks to his ability, hes actually a 5/5 for 3, and all your big booty Treefolk are going to get a huge boost