Most of the OP has already been covered and debated to death. But there's a couple things I want to say about this bit.
About videos showing off RP2 before it was released: did you notice all of the issues and bugs that RP2 (and plenty of other mods on Forgecraft) had? Seriously, there's a reason why they get to play with mods first. It's because they're beta testing. It's because the mods aren't finished or bug-free. It's because their server probably crashes FAR more often than servers using the released versions of mods. I recall one of DW20's videos from a few months ago where Forestry multifarms wouldn't accept anything from pipes. Another one where the entire server crashed because of a single typo in a single mod. And so on. I've noticed while watching both Direwolf's SMP season 4 and his Forgecraft 2 videos that he mentions crashes A LOT. Many such crashes even happen WHILE he's recording. Do you experience daily crashes for a multitude of reasons? No? Forgecraft is the reason why.
And please tell me, why the hell is beta testing limited to such a small amount of persons ? What exactly is better in testing there and only there then letting everybody else test too ? More bugs would be reported, and it would be overall faster (Railcraft does it, Forestry does it, etc....). I know some modders don't want to do it because a lot of people use it as an actual release instead of a beta and do not report bugs, but in the end this doesn't change anything anyway ! You'll still have more people to test so screw the others.
Crashing servers really ISN'T the reason. You don't want crashing ? Then don't use the beta !
I'd really love to know what really are the motivation for very closed beta other than to favor their modders, youtubers and streamers friends, which is perfectly okay, they do what they want, I'm not crying about this.