I hate to burst your bubble, but WC3 was still MIDI's inflight, and the movies just used Rolandised versions of the MIDI music. I can't be certain about WC4, but it also sounds very Roland to me. I should know, I own a Roland E-96, which is, btw, the best E-series keyboard they've ever done, perhaps with the exception of the millennium special EM-2000. All other E's (even newer higher numbered ones) had lesser specs than the E-96 because otherwise the high-range Es would approximate the much more expensive low-range Gs too much and no one would buy the G-600.
I just loved playing WC3 with my E-96 hooked up to the MIDI port for the music. With it's 18-bit 48kHz stereo it sounded even better than the WC3 movies or KS.