I was very wary of Blueprints, but after playing a bit and seeing just how they work, I was sold. Same with using C++ natively; it seems daunting, but you're calling the same methods your Blueprints do, it's almost drop-in easy.
Definitely it's gonna need to make some progress, but the gap is closing.
I imagine this will gradually improve, but for now it's really not an appropriate engine for that class of games. Anything from LÖVE to Unity works much better.
We got some pretty complicated HTML/JS/CSS up and running and nicely integrated (js talking to blueprints and vice-versa) in under 30mins. It's fully backed by Epic now through a grant.
It handles video and audio nicely as well. There's little reason to consider using the inbuilt UI stuff when it's so easy to leverage existing HTML skills to build it out.
A few of us from the Valve development community, EA, and Blizzard wrote this as a side project.
http://www.andrewmcwatters.com/grid/ https://github.com/Planimeter/grid-sdk
Does it support cross-platform releases to consoles, mobile, and PCs?
LÖVE's team moves really slowly though, and we release updates on about a weekly basis. We'd eventually like to move off of them but keep a similar framework API for people to migrate away from.