No In CE, the pistol had slow acting bloom at high ROF's, but not nearly what Reach has. Some people never notice. Halo 2 and 3 never had that. In each burst in Halo 3, each bullet that comes out is increasingly random, but that is not controllable like bloom.
There is NEVER a perfect firing rate. Someone can always shoot a little faster and get lucky. You can use the honor system and pace correctly given a certain range, and that will almost always be outdone by someone who shoots just a bit faster.
Everyone spams at close range. The range where the line between spam and pace starts to blur at mid range, where a majority of battles happen. This is terrible for competition.
Bloom is a manipulation of randomness. A lot like poker. You can set up a situation well, knowing full well what you are going to do, and not what your opponent will do. Then, once both people commit to their strategies, the determining factor is luck. Always luck.
THAT is why bloom is a bad mechanic.