Well..., for those recent and very often changes we had for COH1 including the replay files - it would be quite hard to develop considering those.
Since we do not expect any updates for COH1 from now - it could be possible to deploy this. Though it would then divide already small community in those who post/download replays in coh2.org or GR which is not good thing.
Great feature would be to link GR replays on COH2.org and display them therefore same way as COH2 replays are displayed. Idk how's with all the permission things - but no need of DB information is needed for this since get responce could be parsed
Anyways - that's quite a lot of work.
How would this split the community hardly anyone goes on GR anymore, the ones that do simply do it for replays, example, literaly all the people who are in my tournament signed up through this website, and literraly no one, and on my last tournaments all combined around a total or like 3 joined through GR.