The Miz is just gold and it really doesn't matter if he's a an heel or a face, he always delivered with a stamp of great TV on everything. His gimmick changed and he isn't the annoying face, if anything he's the new cool guy in town. The joke that you gave out to try to make fun of him because he wasn't clever or anything like that is just stupid, because all in all the joke worked. CM Punk said "Yeah, you suck!" and The Miz just replied "No, I don't... But your mom does." So if anything the guy responded with a good basic joke, obviously he was talking about how CM Punk's mother likes to suck dick.
Now being very serious The Miz is a great performer, he can play both an heel and a face and still have a great deal of supporters. He turned face because he did everything he had to as an heel, and they started to twist him a little bit, they made him grow a beard and look more manlier. They put him in a movie, and they started to pave the way for his inevitable main event run. He has been gold with his MizTV segments without even getting into a feud of his own. He's just getting noticed for his great mic skills, and when I say great I put it probably in the top 3 currently, in fact I could hear Miz saying those "stupid and non clever" jokes all day, if that meant I would never hear CM Punk talk about respect or John Cena talk about how he loves us again.
The way that they are building his face turn has been very good and it's been very well handled in every aspect of it. He gets some wins over some midcard heels but he gets TV time with top heels and even top faces and he barely has to wrestle so it's a good usage for him since everything is full. In my mind he is one of the favorites to win the Royal Rumble 2013, it may not be the most logical choice thanks to guys like Ryback or Randy Orton, but he has to be considered given the fact that they are trying to put him back into the main event scene.
I don't get the hate he gets from internet smarks, I believe that the fact that he didn't started in ROH or an indy promotion as to go against him nowadays, which is stupid. In fact I can't see another guy besides John Cena that has that energetic charisma and that great way to handle a crowd like Miz has. Granted it's all very new for him, but he gets the job done and in a very good way. He's the 4th face of the company nowadays, and in terms of popularity he's gotta be the 4th most important guy in the company. He's a marketable guy, very solid in the ring and fantastic in promos so he'll do fine being a face or an heel, he just needs a storyline, and I mean almost any crappy storyline works for him. He build an IC Championship Match at WWE Main Event in less than two weeks and he made people care more about that storyline than whatever Sheamus and Show were doing at the time.