But if your CPU goes up for an unrelated reason, the odds of it being covered under warranty is small. Actually, they can (and should) void the entire warranty on the computer for even unrelated work, such as battery replacement, due to user modification.
As far as the lasting longer idea, the paste redo may prolong longevity, but the MBP does not have a history of poor longevity...
I`m in total agreement here.
Not to say don`t do it, but you have to accept the possible consequences of carrying out work that will invalidate your warranty.
In short, if you`ve stumped up for AppleCare then there is no point in carrying out this procedure, if it cooks itself you`re covered.
If YOU cook it, you are`nt.
I`m quite in agreement that Apple should not be covering things like this under warranty it`s your choice to mess with your machine.
I do have sympathy OP but you chose to take the risk...