Case selection is very critical when it comes to planning a "no-prep" or minimal prep case. If the teeth already look bigger than average, it may be more difficult to do a no-prep veneer and have it look natural. If you have any doubt about the outcome, you can always do a mock-up and determine how it will look. If it is a true no-prep case, dentist can order a wax-up from the lab, fabricate a matrix and "mock-up the teeth before any irreversible proceedure is done. That way there is no reason to have buyer's remorse.
No-prep veneers are "theoretically" reversible, although I believe it is impossible to guarantee that the porcelain can be removed without any enamel loss, I feel it can be done carefully and nearly free of enamel loss. But - if you are happy with the outcome why would you do anything? That is why I would recommend the mock-up.
People sometimes don't think of orthodontics as an irreversible proceedure, but it deffinitely is. In fact, I believe it is more irreversible than "no-prep" veneers. In addition, when the orthodontist removes the braces, they have to remove the resin bonded to the tooth and polish it up. I guarantee that if they remove the bonding resin completely there will be enamel loss.
It is important to use a good lab. I would recommend a feldspathic veneer and request that the ceramist use enamel porcelain at the gumline. This allows for an invisible margin where the tooth and the porcelain meet.
Take a look at the first set of veneers on the Youtube video, they are no-prep veneers. I don't think they look too bulky.