I don't know about right now, but last I looked (~1 year ago) the 1TB 2.5" drives were not standard height. Some people were able to jam them into specific laptop models that had enough room (or flex), but that was it.
Another way to look at it is to see how many bare drives are being sold at those specs (1TB 2.5") vs. external drives. The bare drives won't sell as well if they are a non-standard height (at least I assume they wouldn't).
Samsung and WD are selling 9mm (standard height) 1TB drives, and have done so for almost a year. I think Toshiba or Hitachi recently released a 7mm (extra slim) 750GB drive. Seagate has been selling extra thick (15mm) 1.5TB drives, but only inside external enclosures, for some time now.
Many laptops will also accept the thick 12mm drives you're referring to.
Well, they are standard enough to fit into a MacBook Pro (even the 13") so I think they were quite popular, I have one, and know quite a few other people that do.
Another way to look at it is to see how many bare drives are being sold at those specs (1TB 2.5") vs. external drives. The bare drives won't sell as well if they are a non-standard height (at least I assume they wouldn't).