This sounds interesting at first but so far I had thought of these following problems. Do note that I will be comparing it to taiko's counterpart.
Firstly, I think that it's not really fair to give it a miss considering that mappers will be using this note to emphasize a beat in the song and having it to miss after successfully single tapping it kinda defeats the purpose of using this note
This brings us to the next few questions (unless you can convince me and/or some of the people here the reason missing that note through single tapping is fair). What would happen if you only manage to tap one instead of 2 keys? Do you get something similar to a slider break? Or do you get only 100 and keep the combo count after single tapping that note? If you are keeping the combo count, how would you determine the accuracy of it if you single tap it?
The way this note works in taiko is to have a standard score as a single tap note if you single tap it, and doubles the score if you double tap it. But then, if you require both keys to be pressed to clear it, it will get extremely complicated.
If you do it identically with taiko's counterpart however, that almost defeats the purpose of this note as we can single tap and still get 100% accuracy out of that note anyways, unless we are talking about fighting for top score of the map which in case would make stuffs even more competitive for top 1 scores farmers. But then, if we were to implement this just for the top 1 scores farmers, we might as well remove the 477 spin limit.
Don't get me wrong. This note is interesting and it opens up a lot of new possibilities, patterns and stuffs, but IMO it's either too complicated to implement or serves no purpose compare to a singletap note