NIN is completely fine. They don't do well in brawls compared to SAM MNK GNB and they lose a ton of their damage if you force them to burn mudras on Huton or Meisui for defense. Shukuchi is almost completely ineffective as a mid-combat stealth due to server tickrate (it's exactly the same as WoW's "Vanish bug"), being pretty much only just a repositioning tool and *maybe* they can get the Assassinate off if they hit it instantly. I don't think Shukuchi needs changes, though - I think being unreliable in combat is fine. Maybe they even gave NIN two different defense ninjutsus for that reason? NIN is entirely about skirmishing until they can go in for the kill with Mug-Bunshin-Assassinate-Aeolian Edge or with their LB, but timing the LB is very tricky unless they're pretty much dead already... in which case MNK Meteodrive is just a flatly better version of that because it charges faster. If you ignore NIN and let them constantly peck away at your back line... yeah, they're a hassle. But if you sit on them, they will struggle to do much more than throw daggers and mudra at people, and that can be healed through without too much trouble. Very good class, but there is plenty of counterplay. Counterplay to NIN is very reliant around recognizing their cooldowns. Almost all of their meaningful damage is in their mudra charges (2, each 15 sec) and Bunshin combos (5 charges, 30 sec.) If Bunshin has been used, NIN has almost no kill potential compared to any other melee. Meanwhile, MNK and GNB pretty much never *stop* dealing damage, it's just less bursty than NIN's is.
BRD doesn't need buffs. They're not overpowered, but they are quite close right now. I'd like to see Heroes' Fantasia not require LOS, and in exchange maybe reduce the silence to 2 sec (since LB is now a guaranteed buff to the team instead of "whoops the idiot DPS walked around the corner even after I signalled I was using it") with a slight potency boost. I think a LOT of people underestimate how important damage up/down effects are in CC, probably because in low skill games people just get blown up while being stunlocked because people don't know how to position themselves or initiate properly. At higher skill levels, those buffs are incredibly important. Remember, BRD+SCH/AST is pretty much *+20%* damage for your entire team with pretty much permanent uptime as long as the group is in combat. That's an absolutely monstrous swing in your team's favor.
I do agree that RDM is still a little overtuned. Not overpowered, but they're definitely a bit stronger than they ought to be. Their LB basically ignoring Guard due to how it works (as well as their dot) is the biggest issue and should be remedied. The potency probably doesn't need changing, just changing its operation so that it doesn't "ignore" Guard.