Here is a chart of the weapons of Modern Warfare 3.
The fastest primary on that chart has a killtime of 0.1 seconds.
The fastest primary in Halo 1 has a killtime of 0.6 seconds.
The fastest primary in Halo 4 has a killtime of 1.4 seconds.
Even if killtimes were buffed to CE’s level, they would be nowhere near Call of Duty’s.
You can complain about them being too fast or too slow all you want, but we do not have “CoD Killtimes”.