While the majority of the upcoming shows seem promising, I wouldn't say it's a "renaissance" per say. To me a renaissance requires something truly innovative, something that's memorable. A lot of animation studios had that "memorable" factor in the majority of their productions throughout the 90's. Nick and Cartoon Network were reviving creator-driven shows as well as the idea of cartoon shorts, Disney pumped out a string of some of their most popular movies, and WB was also making magic with people like Bruce Timm and Tom Ruegger, with the help of Steven Speilberg.
It seems to me that nowadays the majority of the aforementioned studios are trying hard to recreate that spontaneous magic which crept into the animation studio back in the 90's. Cartoon Network is trying to do cartoons with more mature humor (but in my opinion they're kind of missing the mark a bit), Disney is attempting (or was attempting) to return to their well-known hand-drawn features with the musical Princess and the Frog, and WB has more series' in production than it has had in the past few years. So I will say that I have noticed that these specific studios have been trying to recapture the glory that was the 90's animation industry, but there's still a certain "spark" that's missing from the majority of cartoons, whether they are made for TV or theatrical. Sometimes I think that there isn't really a way to create an animation "renaissance", and that the renaissance just happens spontaneously. Who would have thought that after a couple of decades of an animation rut (the 70's and 80's), the huge animation boom of the 90's would happen? The reason it did happen is simply because the right people were at the right places at the right time. Good animators and cartoonists were given good opportunities, and the execs in the business were at the right studios doing the right things.
Conclusively, I don't think there's a WB renaissance going on yet, nor do I think that any of the other studios- Cartoon Network, Disney (both theatrical and TV), Nick- are experiencing renaissances either. The only one I can say might be experiencing one is Pixar, and it's glory never really ended since it all began with Toy Story back in the day. But the main thing that matters is that WB, as well as other networks, are trying to create good animation again. They still have a few kinks to work out, but trying is always the first road on the path to success. Maybe in a few years from now, when the industry has shuffled once more, we will have another renaissance just like the 90's.