Okay, I'll play. But I'm
really reaching to come up with something that makes the 7mm08 less than excellent for deer. (I love my 7mm Mauser which is basically the same performance in a long-action)
Umm... it doesn't have the satisfying and ear-shattering blast of the magnums. Boom fun.
If you're planning on shooting deer beyond X yards (not sure what that might be--a lot farther than I could ever expect to see a deer where I hunt. Let's call it 500yards), it might not have enough umph.
A .308 can (okay, almost all can safely) shoot cheap(er) surplus ammo for practice. A 7mm08 is limited to more expensive factory ammo or handloads.
It's lacking the history of the .30-06/8x57/7.62x54R/.30-30/etc. None of that will matter to Bambi.
Okay, I give up. There's nothing wrong with the 7-08. I'm a fan of the .30-06 myself, but for deer anything from the .243 (heck, even the .223, but in VA it has to be >.224" for big game) to the .375 H&H could be (and has been) used to good effect. Some perhaps better than others, trade-offs blah, blah... pick the one that strikes your fancy in a gun that strikes your fancy in a recoil-class you can handle and go for it. If you can handle the recoil of the magnums (and the price of the ammo/gun) go for it. But you (probably) wont
need it for deer. If you're going to be doing some long range shooting (either hunting or target/plinking) as well, the magnums might be a good idea.
Happy Hunting
You know, there's nothing like a good gun discussion to make this preacher's kid a raving moral-relativist.