M&M makes me think a little of Storyteller System’s cornerstone combat quirk (applying a damage pool vs. a separate defensive stat after to-hit is rolled, plus the whole “damage boxes as increasing states of harm/disability” rather than the classic all-or-nothing HP thing) combo’ed with a massively stripped down d20 variant (Ability scores are basically just carved down to the ability relevant modifiers rather than the tried-and-true 3-18 scores of yore, a change I’ve actually recommended for systems like D&D and Pathfinder a couple of times), so the combat math takes a little getting used to.
So, I do agree it’s easy to build a character that is “bad” insofar as it interfaces poorly with that system. If you lob all your points into overcoming a to-hit defense and have no capacity to breach the “actually taking damage” defense behind it, for instance, you might well be the world’s most accurate pea-shooter, or what have you.
But once you get used to it, and the whole “give and take seesaw” side of the math (Pump your your ability in this area? That will lower the max amount you can put into this linked ability over here!), it’s also easy to see the balance elements the designers intended to leverage to keep things from going nuts. Yeah, there’s weird-out powers that can break that molding, but for the most part, it does a good job of maintaining this leery sort of “Tough but slow vs. Fast but fragile; accurate but weak vs. inaccurate but potent” balance point among characters of similar power level.
AKA, as initially: character creation can be intense. Strong GM-player communication to avoid the pitfalls is definitely, definitely recommended, as you noted. I’ve been lucky to play it with folks who know the system well enough to guide folks away from the bad ideas and toward really cool, expressive ways to showcase their powers.
I mean, this is the same system where I built my poser-goth teenager empowered by an ambitious Unseelie Court Fae princeling who uses his crippling (albeit false) depression to make foes wallow in their own misery until they pass out, totally stole the chic looks of The Crow and the bitchin grapple-chains of Spawn because he used to watch those movies with his dad, and has just enough facial hair to get the “Looks 2 Years Older” benefit (useful when stealing cars. I mean, until he has to drive one).
All told that was about 30 minutes of chatting between me and one of the GMs and tapping buttons in Hero Lab.
Shit, I’m just gonna come out and say that full Hero Lab compatibility alone makes M&M the system to go with for superheroics these days ;-)