A very interesting topic indeed. I have myself often wondered what Valyrian could be like and even drawn one or two ideas about the language. As you say it is most interesting for conlangers. I do believe they will try to fit Valyrian into the whole project, as it appears in the subsequent books, I think they couldn't get a better conlanger for the job. David Peterson's work on Dothraki was awesome I hope they commission Valyrian also.
But it'd be interesting to know more about Valyrian. I've always pictured it as semi-Britano-romanic in sounds and names, and with something of its own spin in it.