Waveform List is available!
http://cdn.roland.com/assets/media/pdf/E-A7_Waveform_List_e01_W.pdf

First impression: Lots and lots of ethnic sounds. But restrained quality with grand pianos: There's only one piano with 3 velocity layers (waveforms 1-18, "Pno SX" in mp, f and ff, each in 3 variants), two others with 2 layers.
But the fact that Roland publishes a waveform list, not only a sound list, reveals that the E-A7 obviously has synthesizer functionality, for pure arrangers waveforms are not shown.