As I've said elsewhere, something like a very compact 15-85mm or a slightly bigger 15-135mm would be great as a do all lens, for work use f3.5-5.x
As for more... I'd like to see more fast ish pancakes, a really fast f1.4/1.2 prime, plus a pair of tele zooms, one compact covering 55-200mm, a second larger lens picking up from 100mm ish to 300mm ish, then I'd also add a pair of macro lenses, say, 60mm & something longer.
I'd also like to see something different, a lensbaby specifically for EF-M
But priorities first, let's get a cheap Eos-M and a high end Eos-M on the market to make a range of three cameras