Yes, I have seen Doaz's BMS Creator, and already tried it out. I really like it, particularly the time selection tool and waveform display.
But for now, I still use BMSE because of another application I wrote a year ago that provides BMS scripting support via JavaScript. As it communicates to BMSE via clipboard, it is a little hard to use.
And if I have a lot of free time I would like to add some scripting ability to BMSC too, integrated if possible. Just an idea.