So in other words, don't buy these unlocks if you haven't already, since they've already told us there will never be more class missions. Especially not with Cartel Coins, they're not worth it.
Both of them are useful when leveling an alt that's going through its class story. Just because there are no individual class stories for 50-55, it doesn't mean the unlocks/boosts are not useful.
And it wouldn't have made a difference as to how useful they are even if there were individual class stories in Rothc. There would've been like what, 10 class quests? The unlocks/boosts would remain pretty much as useless/useful as they currently are considering the general boosts will always be better than the individual ones (class, flashpoint, space etc).