This is a subject of some interest.
Here, where I live, shots are never more than 200 yards, and most occur within 25 to 50. (See the attached photo for a typical view on my farm.) As a result, lever action .30-30s have probably taken more whitetails in Virginia than any other rifle-cartridge combination.
However, there are times when I'd rather my Remington 700 VSSF in .270. Though legal here, I think the .243 isn't quite optimal, but a lot of people like this caliber. It just strikes me as a little too marginal if the shot isn't perfectly placed. I don't like having to chase through the brush and rhododendron thickets after wounded deer. The .270 overcomes that objection. And, it has the advantage of being pretty flat-shooting at the distances I am concerned with.
I agree with you that unless you're shooting whitetails at extreme distances, the 7 mm maggie and the .300 are too much. Elk in Montana, yes. Whitetails in Virginia, uh, probably more gun than is necessary.
My neighbor has an old rifle in .35 Whelen and he routinely gets his limit (and more

) with it. He's much better at fieldcraft than I am, which I guess is the point: the closer you can get, the less critical the caliber once you exceed the legal .243 threshold.
I plan on pressure canning a mess of venison this season. They are thick here this year. I saw three 12-pointers together a half mile from the house yesterday, and I've scouted out their path from where they bed down in a big pine thicket to their water source at a nearby creek.
Anyway, I wish you a bountiful whitetail season, regardless of the caliber you end up with.
Bullseye