If you can land Bind reliably, it really won't matter too much what sub you choose. /NIN's just a bigger safety net for resists or allowing you to be more offensive in eating a single-target to fire out your own. Of course, Genbu could be tickled to death regardless of sub. You won't be soloing Kirin, though. Honestly, I'd say you got a Genbu's Shield and Wyrmal Hands to just call it a day, but if you do ever consider leveling another job, the other drops could be temporarily handy until you pick up Abyssea-based replacements.
Taru's basically the best race if you're looking to go pure offensive caster on RDM, but if you think you might be regretting the aesthetic later on down the line, I'd just say to think about it a bit more.
Far as want goes, RDM's trigger options in Abyssea are limited and we're certainly not the best healers with WHMs having both Cure 5 and 6. You'll probably get invites to stuff eventually if you're just PUGing, but we're hardly in the monopolistic position some argued for back in the ToAU days.
And while you didn't ask about this, I'll preempt a bit of "What to...
" when it comes to Abyssea since another poster asked kind of recently. Obviously you still have some work ahead of you if you're starting from scratch, but eventually you'll be digging into Abyssea.