Purely aesthetic issues are definitely not covered by Applecare on any product. In fact, if there's even the slightest chance that visible damage caused a problem with the use of the device then Apple will generally preclude you from warranty coverage, but that's where Applecare+ comes in. These devices always get swapped out through Apple service, so you are right about how things would go in the event that you crack your screen or physically break the product. Pay your $49 and get it swapped out, regardless of how many issues the device is having. The thing you want to be mindful of is my initial statement. It will not feel like fun to have an issue with your device that warranty would normally cover for free but be told that you have to pay due to excessive scratches/dents/dings that a case would have protected you from. Apple has every right/reason to look for reasons to not cover issues for free. Just something to keep in mind, and I used to work in Apple retail stores in case you're wondering why I'm saying these things.
It certainly will be interesting to see how AppleCare+ will work. When it was an all or nothing proposition (AHD not covered, at all), other than water damage, Apple Stores were very good about replacing/fixing even products that had visible signs of being dropped (but not a cracked screen on iPads and laptops of course, but they have covered broken hinges on laptops). Now granted, if you told them I dropped by MacBook and now it doesn't work, they would not cover it. But if you tell them yes I dropped it before and it was working fine. Now it doesn't work. That likely gets a repair/replacement under warranty, or sent in for futher evalution in the first year for anyone and during the extended AppleCare warranty if applicable.
That's been my experience, anyway. Other than water damage, Apple Stores have not been looking for any reason not to give warranty coverage.
When you worked in an Apple Store, did you have many "not covered" by warranty when it is not a water damage or admitted abuse of the product? And let me know what store that was so I can find a more customer friendly store.
Just a guess, but I suspect the biggest difference will be the AHD clause will get you a new iPad for $49 for a cracked screen or minor water exposure whereas previously you got nothing.
Anything that would have been covered under the standard warranty will be covered is my guess for the first and second year under AppleCare+ for no fee.
I don't think scratches will cause the $49 fee (if that were the case, then scratches/dents for everyone like me, who doesn't buy AppleCare+, would void the warranty because by definition anything that would trigger the AHD fee is not covered under the regular 1 year warranty). Dings and dents may depend on what failed and where the dent is in relation to the failed part.
Buy a case if it makes you feel better, or if you're hard on your equipment.
I think you may be over thinking this a bit. What you are concerned about could happen. But that said, I would be surprised if there is any difference on what has been repaired for free under standard Apple warranties before, and now under new AppleCare+.