In none of the COD's were you able to switch it to 3rd-person. Although they did make it an option in MW2, it will only be allowed in PRIVATE matches. Meaning non-ranked games.

So, I see no problem with this. I remember back in the CS beta days, it used to be a 3PS as well. But that was easily exploited to look around walls, so they took it out.

3PS will NOT be a problem in this game. Private matches are for teenies.