Yep. People have already put in the effort to finish ops for Tatooine. Adding a new character to the ops that wasn't around when ROTE came out and still isn't accelerated could push some guilds back a ways on completing Tat ops. And some of those guilds could be relying on completing ops to make the Reva mission easier. It's an unforeseen obstacle that players should not have to deal with. For this reason, the operation character should have been a softball. They should have used a very common character. A decent number of operation characters have been GL reqs, what's one more?
It is not the fault of the players that CG messed up by putting Fifth Brother in that slot and then left it unchanged for a year. Players/guilds shouldn't be potentially punished for this.
/e Leave it as is for now, because guilds have probably already had players dump resources into chieftain to get ready. But in the future, any changes should be mostly non-issue characters.