How about a link from the Island to Richmond. this would save having to have the different courses on different days. It would increase size without having to make new terrain.
First because Richmond is a one direction route.
Richmond being a single direction shouldn’t make the slightest bit difference.
Of course having a portal between Richmond and Watopia would break Strava integration, so my proposal would be to just lift up Richmond and recreate it in Watopia. You might need to change some of the surrounding scenery etc but there’s no reason why it couldn’t be integrated, maybe add in a few extra turns and side roads. Or rename it Watopia City.
So rather than having to choose I can do a Watopia ride and a Richmond ride as part of the same session.
I fear however boring legal agreements from Virginia state or the UCI may prevent that approach.
Watopia will keep expanding until there’s no more room left on the island, I’m sure of it. The mountain route is the next expansion. I’m sure there are more planned (but not shared publicly).
I know everyone would like both more routes and the ability to chose but I don’t think Zwift is ready for that yet. For the first time yesterday, I saw 1000+ riders online. There were a couple of group rides going on and then your mix of those doing workouts, recovery rides, or just having fun. Watopia has grown since the early days and with 1000+ riders, there were enough people to fill out the island and give most people either something to do or someone to ride with. Zwift felt “full”, that is, it felt like I was somewhere surrounded by lots of other people who like riding bikes like me 
Now, think if there were only 1000 riders online but you had many courses to choose from? Your chances of being on the “right” course with people that you could ride/have fun with would be significantly reduced. One of the greatest things about Zwift is that no matter your agenda, you get to ride and interact with people from all over the world at any time. I’d hate to be riding on some course practically alone. Even when I’m doing a custom workout, its nice to see other people, pass them, get passed, or chat (in between intervals).
Richmond isn’t my favorite course to ride. Even with 500-750 riders, it sometimes seems “empty”. Large gaps seem to develop between groups of riders. The environment is pretty boring as well. Especially when you compare it to the new Ocean Blvd. expansion! That being said, if you split up 1000 riders between Watopia and Richmond, Zwift will start to feel more “empty” again. Add even more courses and you get the drift I hope.
So I think we will get there. Zwift will get there. There will be more courses and choices but only when Zwift is ready.
Just my 2 cents.