Norway did it in 2015, and it seems to have been a success.
There has been surprisingly little debate about it here in Denmark. I haven't heard a single argument against it.
It should be noted that the draft is for training only, and that it's possible for pacifists to opt out of the military training by doing work for other institutions.
Personally I think it might be a great help for modernizing the military, because they'll need to rethink the old "one size fits all" procedures.