I have to wonder if you actually play MNK? You realise RoE requires a hit to be proc'd right? You don't just instantly get 30s free positionals. In E1S you have to pick where you actually want to RoE because some parts are better than others. But that doesn't mean positionals are meaningless, there can be times where you're waiting for RoE to proc, but can't hit positionals (E2s) so you have to also use True North just so you don't miss out on the 150 extra crit potency from bootshine. You're examples are very simplified, but it really doesn't play out that way in a fight. The last phase of Titan is the exception. Even E2S needs planning when to use RoE to make the most of it. Just because you can have it sometimes doesn't make it worth it if you'd be able to hit positionals regardless.
Hence buff SAM... at max it needs a 2%-3% increase. It doesn't need much. Also, easy upkeep of buffs but ignoring SAM having 40s buffs?? Selfish DPS should be higher, i agree, MCH and SAM are the outliers here. BUT, they should not be higher when looking at FFLOGs because that takes into account rDPS and is how the jobs are ranked.
You include cast times being a problem for BLM but discount positionals being on every GCD for MNK? Or just the fact that Melee have to clench their asses to get their extra GCDs in not to miss out on uptime? This archaic thinking for BLM is why it's so overpowered compared to the other casters. BLM has the best on demand movement at minimal potency lost compared to every other caster. BLM hasn't had problems with movement since Stormblood, saying it has to stay casting is the same as saying 'Monk, (or just melee in general) have to do positionals, and yes, before you start spouting about "free positionals on MNK" I already mentioned you are using perfect scenarios in your arguement which simply doesn't happen in a fight.
We're 8 weeks into Savage, there's really no point not to buff the undertuned jobs. It's not like buffing them will break the game, the content has been downed already.