Uh, no. Not all Nagas are a problem. Some of them are legit fun and overall ok at best. There are one or two problematic of course but it's not the entire tribe.
Also keep in mind this is in fact a new tribe. Much like when DH came in as a new class and they had ridiculously strong cards when the class was brought in. Same concept.
If DH had come in with week class cards, people would've bitched all over to high heaven that DH was "DOA" and a useless waste of space.
IF Nagas came is with week cards as a tribe, people would've bitched just as loud about the tribe. Much more so than the odd poster complaining about the nagas power level. So of course giving them decent to very strong cards in their introduction was the smart choice.