I agree with Perchant's rant on being vulnerable. In the last several games I've played in, I've had characters who were, in some situations, very easy to take out. Whether I could get away with that or not is often dependent on who is running the game. If the game is going to be a grindfest splatterhouse grimdark murderparty, then perhaps playing the squishy one isn't such a good plan (though I wonder why you're playing that in M&M). That said, if you're playing something heroic with a GM dedicated to maintaining that theme, they you shouldn't feel like you'll hold the group back. A good GM isn't going to punish you for your stat choices, but rather work with them. All the best games I've been in never feel like GM vs Player match-ups, but ones where players make the inefficient choices to encourage a more nuanced and creative game.

It depends on the GM, and whether the game is combat centric. If someone applied to one of my games with a character with little or no defenses, then I would probably start working on encounters to mesh with their skill set. Its probably a knee jerk reaction to my AD&D days where everyone ended up failing on a 1 to hit, and having a -10 armour class. Of course it makes encounters easy if you assume everyone has the best of everything. All pervading sameness makes GMing much easier.

Still in the current game I am running, I statted all the characters myself. As Witchslasher mentioned, having defenses within 2 points of max is useful. So all the characters have active defenses ranging from 8-12 for PL10. Personally I would love to run a game where people ran problem solving characters where combat was the least preferred way of resolving a conflict (kind of like how it is in the Doctor Who: Adventures in Time and Space RPG). But I don't see a lot of love for that sort of game.

You're not looking hard enough.

I tend to leave one of the defenses at -3 to PL, unless it's a character that is explicitly well-rounded. Every good hero needs a weakness. Troperific.

I don't see a lot of love for that sort of game either. Part of that is because of the comics and cartoons that M&M players like to watch (very combat oriented usually) and part of that is the system (which I LOVE!). It can be done, as I'm sure you know, but since about 80% of all the rules, powers, advantages, skills, and examples in M&M are related to combat, that's the sort of game it tends to produce. When 8 out of 10 tools in your tool box are hammers, everything starts to look like a nail.

I'm a huge fan of M&M, but I only break it out when I want a cinematic combat sim . . . which I do very often! :-D

Well it certainly is working well for the Maid game. I purposely decided to dive into combat so I would be forced to learn it, and its working quite nicely. More and more its become my system of choice.