Power Mimics are unusual. While they may have powers of their own, they can copy the powers of other individuals, to a greater or lesser extent.
Power Mimics tend to have 'slots' that they fill with powers. Most fill slots with one power per slot, although Mimeo can fill his slots with one person's powers per slot; a large difference, if one of those individuals has lots of powers, such as Tennyo.
Duration of power copying varies. Some seem to maintain a power until they free up the slot to copy another power, while some only retain the powers for a finite amount of time. In rare cases the power copying is permanent. This happens with Sphere, whose mimic power also permanently imprints on Pinball's BIT.
Some produce copies at a lower power level, while others can produce full strength copies.
Some are touch mimics; all they need to do is touch you to be able to copy your powers (e.g., Sphere.) Others need to actively involve the power to copy it; Mimeo is this way, the power must be used against him for him to copy it. They may or may not need to be aware of the power to copy it; Thunderbird copied an avatar power with no awareness that this had occured until he bonded with Sparky.
Copying powers is not without its dangers. Different powers place different stresses upon the body, and the ability to properly deal with that stress may not be copied as well as the power. Counterpoint experienced this when he copied Chaka's Ki powers; except for her prompt action, he would have died due to the stresses placed upon his body.
While Mimeo is able to pick up gadgeteer and deviser and even wizard powers, and USE them effectively, it's for several unusual reasons:
- He's not a true 'power mimic' as we usually classify them;
- He's at a much higher power level than most power mimics;
- He cheated and actually studied how to use each of these abilities.
Most power mimics have the classic limitations:
- They may not be able to get a full-power copy of the powers (like Duplex);
- They may not be able to get the useful aspects of the power set (like copying an Avatar and only getting the power but not the boost from the Avatar's spirit) [Mimeo is very different here);
- They may not be able to copy anything over a set upper power limit (like not being able to copy anything over, say, power level 4, so the best they could do is EX-4 or EN-4 or WIZ-4);
- They may not have the training or ability to use a lot of the powers (like the Wizard power, which is pretty useless without lots of training in spellwork and Essence collection);
- They may have time limits on the length of time they can hold a power set;
- They classically can hold M powers, not the powers of M people (Mimeo is different here);
- They classically cannot mimic powers from non-mutants, so they can run into trouble against power armor, trained baselines, people who are Empowered or Imbued or whatever (like Skyhawk);
- They classically cannot mimic the form of the target (like Counterpoint), or else they cannot KEEP from mimicking the form of the target (like Duplikat), both of which can produce exploitable weaknesses in mimicking;
- Some other junk I'm not thinking of at the moment.
So power mimic CAN be a gateway power, under the right circumstances, with the right person. It certainly is for Mimeo, who figured it all out while he had a Paragon power set, which gave him the power to (among other things) figure this out. Then he was willing to WORK at it. This is a fundamental issue.
Counterpoint could become far more dangerous... in theory. But he cannot change. He is a warrior, and only a warrior. He can't use Chaka's power because he'll never be able to learn to wield both the Yin and Yang sides of it. He can't use Fey's power because he not only hasn't learned any magic, he doesn't believe he should waste his time learning how to do magic. He can't use Razorback's speed or Diamondback's flexibility because he can't physically change shape. He hasn't learned enough background material to be able to use a deviser power effectively. He has yet to gain Phase's power, so he has not learned how dangerous it is to oneself (remember how Phase beat Counterpoint in Ayla 7). He's going to stick with the standard beat-em-up powers: Exemplar, PK brick, Energizer-blaster, etc. because those have worked for him for millennia.
Duplex could become more dangerous... in theory. But she's limited by her own power set. She couldn't get a fully-powered copy of Diva. She hasn't had training in wielding powers other than her own (she has not done the coursework).
So power mimics look good on paper, but have drawbacks. Just like every other power.