When you say the cartridge is "mediocore at best", yes you are.
You cannot compare a scoped .270 to an open sighted 94. They are two different guns for completely different situations. Its like comparing T/C Pro Hunter to a flintlock. With that statement you are comparing rifles not cartridges. Would YOU take that same shot with an open sighted .270?
Your 200 yard shot is not something that every hunter see's in their lifetime. I've been deer hunting for almost 30 years and I've never seen a shot at a deer at 200 yards. Some hunters hunt prairies, some hunt big open lots in Sask., some hunt mountain tops. Then I would want a .270 for those shots. Your situation of shooting 200 yards through hardwoods is really not a good example because I doubt even you could fish a bullet through 200 yards of trees and limbs, let alone see horns. If I did see a buck at 200+ yards, I would not be upset because I couldn't make the shot. I would be upset that I wasn't a better hunter that could get closer. Better luck next time.
Now if you had started this debate 5 years ago I would have agreed with you on certain points but with the newer bullets out there for the 30-30, it has become an even better killing machine. I will tell you right now, if I saw a buck at 150 yards or a little more I could paste that deer just as easily as you can. Plus if something should go wrong and I hit a limb, (we have all done it) I can get back on that deer's shoulder a lot faster because I won't have near the recoil that .270 will have. Right now I am shooting the fairly new pointed LeveRevolution bullets and they have made my 30-30 an even better killing machine. It is flat shooting bullet that drives home big holes (see below).
And YES! My Marlin 30-30 rifle HAS killed more deer that anyone else in my camp.