Your argument assumes that the average person knows Star Trek enough to be concerned let alone aware of the design changes made and it also implies that if the person is aware of the changes that they'll actually care.
Actually, no it doesn't. But I'll expand on that in a moment.
To the average person(non trekkies. there's a lot of them btw) who's even just slightly aware of the existence of Star Trek they'll probably recognize the Enterprise as a saucer connected to a cylinder via a neck with 2 engines, which, guess what: The new Enterprise keeps all those basic characteristics. They're not going to be concerned about anything more detailed than that if they're even concerned at all in the first place.
Yes. That's true. Some people will see this and think "It's that Star Track ship, where Doctor Spock fought the Kling-peaches." And they won't care. Of course, they also wouldn't care if the ship looked exactly like the original version, even going so far as to pull the model out of the Smithsonian. And no matter what, they won't remember anything about the movie after a week's gone by... it'll be forgotten and washed away by the latest episode of "American Idol - Human Sacrifice Edition."
So who's the change supposed to be for? What POSITIVE will it accomplish?
People who pay enough attention to the movie to care... will notice.
Some of them post on this BBS and think that the original sucked and want to see the original "redone." They'll be happy-ish... but undoubtedly will think that they could have done it even better. They'll simply be happy that the "canonistas" (as they call them) have been disenfranchised.
Some of them post on this BBS and think that the original is the foundation upon which all the rest of the stuff has grown, and if you rip up those roots, the rest of the tree will inevitably be firewood. They'll notice, and will care, and won't like the changes.
There are some who are "casual fans" and know, very well, what the ship looks like... and they'll go in and notice "that's not right."
Who, other than the production staff, actually profits from making this sort of change? (And in their case, they "profit" only in the area of ego, not in terms of financial profit.)
If this is really what it implies... an attempt to "over-write" TOS, instead of to "extend and expand upon TOS"... then there's gonna be a permanent, irrevocable schism beyond anything that "fandom" has ever seen.
And that will mean that Trek is really dead. This movie will have just performed a final act of necrophilia.

