I used to use Raid Restore regularly, but haven't had as much need in 25man content. It still would be useful but I don't think it works now in combat.
In fact, I don't think there is a good list of who can move what when (and in combat or not)... as in Promoted people in the raid (A) can't move other Promoted people etc. Things did change from pre-bc which does suck for raid content.
I don't think the raid group swapping functions are allowed to be used by mods in combat; all raid reorganizing in combat has to be done by hand from the raid window. Presumably this is to prevent auto-swapping in/out Shamans for Bloodlust and/or Mana Tide Totem.
If you're having issues with doing so, that's a mod issue, for some reason this part of WoW's functionality is very easy to taint and thus break in combat, so a lot of completely unrelated mods often end up breaking the raid window.