When I watched the OAV, I was pleasantly surprised to find that Tokyo did not revert back to normal; it stayed destroyed(although when I was watching it I felt like crying; I get really into these kind of things ;;; ).

Any thoughts on that?

To me it adds a sense of historical permanence to what happened between the two worlds. Often in anime shows, or just in general movies or TV, there's a magical reversion or restoration at the end of a story that leaves the scene of the story as we originally found it, undamaged. That implies to me that whatever happened in the meantime didn't really have any lasting impact on the characters or the world in general, so that is not the case with the Rayearth OAV's. Even the Rayearth TV anime ended up with a changed world, but that's rather common with CLAMP's other works as well - X/1999 and RG Veda to name a few.

Your opinion makes so much sense, I'm wondering why I never thought of it like that.

D'oh!

So Tokyo plays a bigger role in the OAV? In the anime it was completely unfeatured outside the first episode of the second series and the occasional (But rare) flashback, pretty much every second took place in Cephiro.

To Do List: Read manga, watch OAVs.

Yes, this is true - a lot of the action takes place in Tokyo. In the OAV continuum, the worlds of Earth and Cephiro partially merge so it is possible for the characters to cross freely between the two worlds.