How about kivy (http://kivy.org/#home) for something of a middle ground? It's a python graphical framework making heavy use of opengl via an optimised cython interface. It has fairly powerful access to the android api through pyjnius (which gives direct access to java classes) or pyobjus on ios (which is less mature but has the same idea).
On the plus side, since it's native to the device (albeit with a different interface), you can do pretty well for speed through the already optimised graphical interface and through optimising your own apps with cython or even C modules if necessary. Other pros include pyjnius/pyobjus for api integration as above (some of which is already abstracted as python modules), and neat perks like the ability to mostly develop on desktop without an emulator.
On the other hand, it has some of the same disadvantages as html5, such as non-native widgets. So by no means a perfect solution, but an interesting contender.