Even though nins tp isn't amazing because of high skillspeed on gear / huton, I still rarely find myself running out. Almost all end game fights have constant breaks where you can regain tp so it's not as much of an issue as people will have you believe. Use invig at proper times, don't spam blossom when no breaks coming. It's honestly not that big of a deal, I play daily

mudra lag is actually an input window, where it checks your latency before the mudra input fires off, if you have bad ms it could give you the odd problem, you learn to deal with this from experience and having an above average ms. Again, it is not as large of a problem as people would have you believe, I rarely mess up a mudra and when I do I know it was my fault and it could have been prevented, it's a dummy check mechanic nothing more.

Nin isn't perfect but it's far from as bad as some of the crybabies say.
My only problem with nin is dancing edge debuff needs to last longer so we can use aeolian edge more often.