Of all the jobs to boost, RDM has the least impactful (heh) consequences on how well someone plays taking just job learning into consideration. The rotation at 50 is essentially identical to the one at 70, and heck even at 80, so there's very little learning needed above what you already would have had to learn at 50. E.g. most Jobs need to learn different rotations at different levels, or at least have some significant mechanic added to the mix partway through levelling. BLM is a very good example of this, and requires learning multiple rotations for all the various DF level syncs. Technically, RDM does have some minor differences at lower levels, for example, different balance levels needed for the melee combo. But since the job starts at 50 everyone has to learn these differences from the same starting point regardless if they have the boost or not so the boost doesn't make a difference.