Is it repetitive? Well, yes, but if that in itself is considered a criticism then there are probably better places to hang on the internet than a Mega Man community...
Repetition can refer to any aspect in a game.
In this case, I don't see how you can compare Mega Man's "repetition" to PxZ's.
In PxZ, the battle controls are: A, Up/Down+A, Right/Left+A, the team L+R shoulder buttons and Y for special attacks. That's fine.
Now, in order to preform 5 of your moves instead of 4, you have to time each one of these (A, Up+A, Left+A, Right+A) all while making sure the enemy doesn't touch the ground. If successful, you can preform your 5th move (Let's say: Up+A), combined with pressing either/both shoulder button (and of course Y, if you have enough XP). RINSE. AND REPEAT.
Oh, and equipping skills or whatever, which I'm sure is extraordinarily simple. What changes are more powerful, flashier moves. But when all said in done, it's still incredibly repetitive.
Now, you said Mega Man games are repetitive; maybe the classic Mega Man games, when the controls, powers and stage layouts were incredibly simple. But I can't say the same for the rest of the franchise.
And even then, not only are the classic games difficult as [parasitic bomb], you need impeccable precision for a ton of those stages. The basic act of "repetition" dictates you to do a motion or routine over and over again. I guess in some ways, those games are repetitive, but you still have to maneuver and time your actions through the stages, find weaknesses as well as various memory-esque puzzles (disappearing/reappearing platforms). One little slip up, and you're dead. It doesn't hold your hand.
PxZ has you standing in one place, mashing the same series of buttons, timing or otherwise, it doesn't make a difference. There's not much of a challenge.
And if multiple bosses on one map are the only things you have to worry about, then that's not really good game design. You just plow right through the enemies like nothing and suddenly the difficulty skyrockets with Boss "counter-attacks"? Sorry, I can't swallow that.
I'd also submit to you that the Game Over screen isn't a terribly common sight in Fire Emblem either; rather the game's perma-death system (optional in Awakening) mandates perfection.
But see, that's another point against PxZ; apparently it's difficult to even
lose a teammate. For Awakening, the only way to get Game Over is if your Avatar or Chrom dies.
So theoretically, you could have the remainder of your soldiers charge into enemy territory and have them killed in a blink of an eye. And you still wouldn't get a Game Over. But depending on the weapons you give them, the experience you've grinded with them and avoiding the enemies that they're vulnerable against, can make all the difference between life and death.
That kind of depth can't be found in PxZ.
You said Awakening's perma-death mandates perfection. Well, if PxZ had a perma-death system, you wouldn't have to worry so much anyway, now would you, Shell?