When I practiced in Miami I was constantly asked by patients if they could just have a larger implant and avoid needing a lift, I still get his question in Austin (but less frequently). I would start with the statement if you need a lift you need a lift. Having a larger implant can lift the nipple about a cm or so. Unfortunately many patients are under the impression that they can just put a really large implant and avoid a lift.
The goal with an augmentation is for the nipple to be positioned at the center of the breast implant. If the nipple is not centered on the implant the overall shape of the breast will not be aesthetically pleasing. The other thing to keep in mind is that there are several types of lifts that are possible from a peri-areolar lift, vertical and full anchor mastopexy. This gives your surgeon several options to help you receive the best possible result with the least amount of scars.
I would just be very cautious about placing a larger implant with the sole intention of avoiding a lift.
Please consult your board certified plastic surgeon to help guide you on your augmentation mastopexy.