Fourzerotwo has been rather busy on Twitter responding to the many tweets of the many Modern Warfare fans. Overall, a few interesting points arose...
The first tweet of interest mentions that explosives have been balanced. However, when 402 confirmed what perks would not be returning in the game, Danger Close was not one of them.
Another quick tweet again confirms that Call of Duty ELITE won't be popping its head up inside the actual gameplay experience; anyone who purchases the add-ons won't gain an advantage in firefights, for example.
This particular tweet is again of interest; whilst he (once again) confirms Stopping Power isn't in MW3, he says weapon damage (TTK in this case) makes the game feature it's signature pace. This could indicate the guns in Modern Warfare 2 have a higher DPS (and thus lower TTK) than the guns in Black Ops.
The final one is of great importance; PS3 and Xbox 360 won't have the huge difference in quality that featured in Black Ops, which should be a relief to the many PS3 gamers out there.