I have seen hibernate referred to as hibernate and also Safe Sleep. Apple calls it safe sleep in its user docs, and hibernate in various develpoer related docs.
http://support.apple.com/kb/PH11096
This article describes the process a bit better, but refers to machines newer than yours (and mine).
Read this for details on "Computer Sleep", the term Apple uses for regular sleep when you close the lid:
http://support.apple.com/kb/HT2412
They define Safe Sleep as "In the event the battery becomes completely depleted while the computer is asleep, the computer will shut down." Before it shuts down, it writes the current state to disk. That would include open applications, files, windows etc. It's actually good practice to let you battery run all the way down periodically to cycle the battery, but that's another discussion.
In my case, my battery was not depleted AND the power cord was attached. There is no excuse whatsoever for the machine to enter Safe Sleep, when regular Sleep was called for. I fussed with my machine for a couple weeks with every tweak I could find in these discussion boards and elsewhere. No help. I didn't even consider defective RAM until I just ran out of ideas. That was the last change I made before the machine started to misbehave. I contacted Crucial who gave me the URL for a couple memory testing applications and also asked me to try replacing their RAM with the original RAM that came with the machine. The memory testing utilities showed the RAM was "just fine." Memory testing utilities are limited in scope, and I was not willing to pay for a better utility. Also, to fully test RAM, it can take a week. You start the utility, and let it run uninterrupted for a day, or a week. Sheesh! I don't have time for that. The trivial RAM tests take a few minutes, but might not discover the problems.
I then replaced RAM in one memory slot and tested sleep. It did the sleep thing correctly, waking up in a few seconds (4 seconds). I replaced that proven working memory with the other third party stick. Aha! This stick of RAM caused the hibernate instead of sleep. Instead of taking 4 seconds to start, it took 45 seconds, with the progress bar and all. In fact, it did not start when I opened the lid. I had to press the power button.
Conclusion: one stick of RAM from Crucial was good, the other defective.
I got an RMA from Crucial and sent back the defective RAM and got new RAM when they received my defective RAM. The replacement RAM has worked fine.
All of that said (typed), I am by no means certain that your machine has defective RAM. I am reasonably sure that you have not considered that as a possibility.
BTW, my mid 2009 MacBook Pro has been trouble free (excluding the above mentioned RAM problems). I bought AppleCare when I bought the machine and never needed it.
As for the keyboard keys, I don't get your argument there. Do you want your defective keys replaced or not? These keys are modular. They're not going to replace the whole keyboard for just a couple keys. If one of your car headlights fails, they're not going to replace both headlights.