We always like getting product design suggestions, so keep them coming.
ONE: If you mean 'archiving' games on the discover or browse pages that you've decided you're not interested in, yes, we've got that on the roadmap.
If you mean games you've been offered, you can reject the game and return the key.
TWO: We don't limit what requests publishers will accept. But it's possible they don't use our tools that let them remove games from accepting requests. So as a rule of thumb, only request old games if you think a publisher might be still interested in getting coverage, e.g. evergreen titles, or when a reboot is coming!