SMN is a fun job and nirvana is a fine piece for certain things... if I could only make one mythic? Probably not, but it is unique and isn't just lockstyle. SMN is a bit of a niche job for anything new anyway. It is actually better than people think if done well, but people know how to run with bard geo and cor buffs, smn takes more explaining and it is more small marginal buffs that add up I. A surprising way. Similar to how you could take a sch or whm or rdm in in place of each other sometimes... heck we used pup healer on ep before on gear cleaving.
I will say that depending on your situation, you may either want to finish or just restart something you will use. Your first mythic is the hardest by far. Once you get a process and habit down, and most of all funds to take your weapon through, the assaults become easier and easier as you learn tricks. Eventually you probably level Blu if you do enough mythic fsrming as it helps a metric tonne. Blu, cor, and maybe smn are what I use for my farming. Smn 9nly for the operation omega or whatever it is called with the perdition ghosts. Can get by without though. Would also use it for the fishing one, if i didn't multi box so I could keep fishing while avatar kills the fish. Best of luck!