I am not sure people actually care that much about dimensions.

Most phones today only look thin on promotional material. With the massive camera bump that is sometimes thicker than the phone itself, and the way most people use cases, in the end, you have quite a brick. Also a glass back panel, which to me is one of the worst materials for that purpose, but it looks good on the store stand.

So to me, a removable battery will not affect the phone dimensions as much as it will affect the look, which may piss off the marketing guys, and I take it as a positive!

Seriously, bring back the removable plastic back covers, plastic may look cheap, but to me, it is the best material, and if you put on a case, as most people do, you won't even see it!