And really not up to the Mint Team to resolve proprietary keyboard or mouse issues. It's up to the manufactures to do that.
It's interesting you should say that, because having just swapped the logitech keyboard for a PS2 HP branded keyboard (which is also logitech) lagging occurs as well, but is not as pronounced. Additionally, and as a further step, having upgraded the Nvidia driver to the latest (310.44) yielded little improvement. I'm not a coder, but I get the impression this has much to do with poorly supported *nix drivers, which I well understand.
I'll accept it's not a Mint team issue, but the code has to fall in someone's lap, and even if this knowledge doesn't assist the Mint team, perhaps it will elucidate some of the community. If nothing else FYI have it's uses.
P.S. Am I misunderstanding the nature of HID drivers? What code base is the team using to support keyboards and mice? I realize my knowledge on this subject is flaky at best.