My 2 Cents
Ok, here's the thing. I'm pretty sure I have the same gen MBP as you (bought mine new on July 07, a C2D 2.4Ghz, 2GB DDR2, etc), so its pretty much as old as yours. I use it on a daily basis, as a university student. I would in fact call it heavy usage (which is to be expected of this model in any case). I carry it around inside an InCase sleeve, inside my backpack (Crumpler) every single time to and from classes. Granted, I play some pretty graphically demanding games as well (through Bootcamp), so its not just the physical casing that gets put to the stress test. On weekends, I come home and hook it up to my 23" ACD, and work from that. This is EVERY single weekend in the last academic year of owning the laptop, and on holidays it always stayed connected to the ACD. So as you can see, I use the DVI slot pretty extensively as well. In-fact it's not just with the ACD. Occasionally I download 720p or 1080p BL movie rips and hook up my MBP to the 60" flat screen hdtv in the main living room through the DVI adapter.
Personally speaking, I consider my self careful in handling the laptop, and I have no dings or scratches, even in this very heavy usage. I don't even have the small metal strip above the superdrive slightly bent. My DVI slot is not bent either, and I can guarantee that I use the slot frequently, constantly connecting my MBP to and out from the ACD. Am I lucky, or is this the result of taking care of the laptop? I think my explanation above speaks for itself.
Granted however, few of my friends also have MacBooks and MBPs. One of my friend has a MBP, and his palm rest is in fact slightly sunken, and he does have a few scratches (more so than what you have on your pic). And, reading from a lot of mac oriented sites, I can tell that users have issues with our model of the MBP, with the super-drive getting slightly warped, amongst other things. So I can believe that the super-drive being bent or even the scratches could be excused by the "Genius" at an Apple Store, since the super drive issue imo is a fundamental design flaw that was overlooked, but I digress. The scratches, are in the majority of the cases to be expected depending on how long you've owned the laptop, so even that is negligible when it comes to technical internal repairs.
With the DVI port being bent at the bottom in your case...I believe you half and half not. I believe you when you say that you haven't dropped the laptop. This is possible, since you can get dings on an aluminum surface without actually dropping it, but when you say that the ding is the result of constantly using the DVI port...I find that quite hard to believe, for several reasons:
1. This could be subjective, but I use my DVI port probably as frequently as you do, and there is NO signs of warping or dings on my DVI port in any way, so this is not the result of wear and tear, and I've had my MBP for around the same time frame as you.
2. Assuming what you said is correct, if the ding was the cause of wear and tear...that doesn't explain why the bottom strip of the port, and ONLY the bottom strip is bent UPwards. Hypothetically speaking, even if you were to use brute force and literally YANK the adapter from the port UP...the portion where it is bent on yours should NOT be bent.
3. Likewise, if you were to yank it with force DOWN (if the laptop was on an edge, and the adapter was sticking out, even then the portion where it is bent should not be bent.
4. If you were to yank it horizontally (if the pins weren't tightened) then it is impossible to bend the portion where it is bent on yours.
I don't know, the whole wear and tear causing the ding is kind of hard to believe. How it COULD have happened however, is if you were taking the laptop off or putting it on a table, and accidentally hit that small area of the DVI slot on the EDGE of a surface, probably the table. That would make perfect sense. If you were to have dropped the laptop, then the bottom of the laptop would also be bent near that area, but its clearly not (at least from those pics), which is what makes me think that it wasn't dropped, but rather accidentally hit on the surface of an edge.
The reason why the "Genius" said your AC is suspended could be due to 2 reasons:
1. The individual was being a douche, and was simply having a bad day <-- more probable reason
2. The bent part on the DVI slit could possibly hinder the removal of the case by interference (scraping?) of internal components. As a result it could be a risky thing. I highly doubt this though...since I've honestly seen worse case scenarios than this that have gotten fixed without any questions asked.
My point is reason #2 is going to be a difficult scenario to convince with simply the "wear and tear" argument.
Simply speaking from a moral standpoint though...its not fair as to how you've been treated so far though...I've seen literally idiots come into the Apple Store here in Toronto (Eaton Center), and get away with free fixes when CLEARLY it was accidental damage, so I don't think the inconsistency in the Genius staff is fair at all. And yeah I paid nearly 3 grand for my MBP when I got it (with the AC) and so naturally I would be a bit let down too if my laptop which was supposed to last me for the next 4+ years all of a sudden was being put on halt after 1.5 years of usage. I can imagine how you must feel in that scenario perfectly, but its just that its going to be a very, very steep uphill battle, partly cause some of the damage is yours which is most likely accidental.