Ever since Rapid Fire was introduced into the Call of Duty scene, it has brought a little versatility to some weapons but in general it has brought more cons than pros.
Needless to say it also has brought the same type of weapon to become hard to balance and eventually turning into the most dominant weapon type in Call of Duty games since CoD4 (credit to McZombie).
With the introduction of Rapid Fire on CoD4 as Double Tap (credit to McZombie), all maps were dominated by AK-74u Rapid fire players even maps in which other types of weapon would exploit their advantages far more than a Sub-machinegun. Shotguns would be the only way to challenge the CQ rule of Subs, but it would take incredible skill to deal heavy power instantly and accurately.
Subs are small, fast moving, slightly higher rate of fire, but don't pack a heavy punch. So they would rule short range situations and close combat instead of medium-long open areas where Sniper Rifles, LMGs and Assault Rifles would rule because of high power and better range.
So in Black Ops the Ak74-u had to get re-designed to make it work without being overpowered with Rapid Fire, and still working without having to use Rapid Fire.
Now Sub-machine guns have to be designed to work well on their one and then work well with Rapid Fire without being overpowered.
On MW3 now we have short range maps everywhere with some long range situations where submachine guns completely reign... Rapid Fire+Silencer becomes such an easy choice because it maxes out your firepower capacity without any consecuence. It doesn't even come at the cost of Sleight of Hand now.
Black ops required you to switch Sleight of Hand for Warlord, hindering your ability to reload fast but pushing your firepower to it's max.
While using 2 Attachment Weapon Proficiency does cost you another type of Proficiency but it's a minimal cost, having to deal with recoil is nothing harsh, damage-drop-off is basically unexistent in this game as 85% of the situations are short-mid range.
We come to the following paradox.
Should Rapid Fire continue in Call of Duty games? Since it has been out in 2 different games now it has a consistent player base that has gotten used to playing with Rapid Fire and could deal a blow to the overall Call of Duty player base. But rapid fire also comes at a ridiculous cost of all weapons becoming useless against Rapid Fire Submachine guns in short range situations.
While it does help to place Subs at an even situation vs Assault Rifles it comes at the cost of making Subs the weapon of choice with no match to deal with them except skilled play.
So what's your opinion... Rapid Fire in the next games. Yes or no?
I say we should keep Rapid Fire, but the developer team should actually look at rapid fire and think very well about how they will toll a player for using Rapid Fire (as on CoD4 or BO)... and not how the Dev Team is doing it right now... "Well.. let's just make all guns shoot mighty fast.. why the hell not?"