I decided to run some dungeons as tank tonight and intentionally did smaller pulls stopping near more packs of mobs trying to bait the healer to rescue me. 10 runs and it happened only once. That's not my point though. What did happen more frequently were the DPS running ahead and pulling the mobs forcing me to pull the mobs I did have a hold of out of my Salted Earth.

What I find happening to tanks is they are forced to snag aggro on more enemies than they pull on their own; one way or another, and this has been going on even before Rescue was available to healers (I started tanking back in HW). Deleting Rescue won't stop this from happening. The one time it did happen, I noticed something. I noticed that if I had to choose between DPS pulls and Healer Rescue-pulls, I'll take the latter. It is actually more favorable since it seriously makes positioning easier, mitigates damage from the current pack since they have to catch up to me, and I also save GCDs. However, I found it to still be inefficient in comparison to the tank Leeroying the whole dungeon.

In short: Rescue isn't the problem.