According to people I trust, if you think it's more Ninja Gaiden than Metroid, then you either have never played a 2d Metroid game before, or you have some sort of vendetta against Nintendo. Sure, there are more enemies than a standard 2D Metroid game, but the game isn't exactly punishing. Heck, there aren't even eagles in this game. I mean, how can you think it's a Ninja Gaiden game without eagles!?
Also, from Team Ninja it's the Sigma team (The guys who ported Black to PS3 and the guys who fixed NG2 for PS3), so they have a good history.