I agree with you. If you are not particular interested in the hold functionality, then having press/press is better. Then we don’t run into problems with stuff you can’t do while zoomed in.
Actually it would make sense to have this on the z key then. It makes sense because we are zooming – and I like the position of the z key on the keyboard better than the + key (thinking of fast workflow and minimum hand movement). I know we already have zoom (if you hold z) assigned to z, but it could work quite well to do this fast jump zoom in 4x, if you just tap your z key quickly. Say, press it for shorter than 250 ms or something. So a quick tap on the z key will jump into your drawing at 4 times the zoom level and tapping z again will jump back. Holding z, will show the large zoom symbol and let you zoom smoothly by dragging as it works now.
I like that! 🙂