I don't think this is really that true, with the exception of vehicle unlocks. BC2 had 25% damage increases and 25% more health perks that made a huge difference between a rank 1 player and a rank 25+ player.
BF3 has some better scopes, and more variety of weapons. I feel that there are no real unlocks for infantry that give you that much of an edge. The base weapons I find are pretty decent, and still take roughly the same number of shots to kill, with a few exceptions (like the SCAR-H being amazing, and the m4 being horrible).
Granted, this might just be because I'm at or above the rank curve:
http://battlelog.battlefield.com/bf3/soldier/ssun84/stats/236558203/