I need a song quantized better than I am able

This song is completely finished. I had someone quantize the drums for me already and I've done some work on it myself, but the finished project still has some timing issues. The whole thing drags in a few spots, mainly the verses. I think it is mostly a combination of the vocals and drums, but some of the other elements might be an issue as well. It is extremely important to me that the song still sounds natural and that no artifacts are created by quantization. I'm pretty picky and this song has been driving me crazy for a while now, so please only reply if you feel confident that you can hear the dragging I'm talking about and that you can fix it. Thanks!

Additional info:
The tracks are cleaned, tuned, and and the song is ready to be mixed. I don't have a hard deadline for this. The song has somewhere between 30 and 50 tracks recorded that need mixing. I'm interested in working with a very experienced mixer. I don't need the song mastered.