We would love to do a first season collection, preferably that would have Bake, Nise & Neko Black. But alas, as Actionfaust mentioned, if Aniplex don't do one, there isn't much chance for us.
If you mean Universe, it makes no odds, different time line entirely, the OVAs came first, even before any of the TV series and have no relation to the TV versions, apart from most of the characters.
It sure would be nice if someone would license and release the continuation of the series. hint hint wink wink
As others mentioned the OVA's are the start of the whole thing so yes. Strictly speaking a number of the other shows such as Tenchi Universe and Tenchi in Tokyo are completely different universes with no relation other than re-using characters. It's kind of like how Gundam has it's main timeline then a bunch of alternate universes that all inexplicably have colonies who hate earth and someone who is coincidentally very similar but slightly different to Char.