First off, don’t create multiple topics on the same subject.
Secondly, Helix is still in development so there will still be changes and new endpoints added over time. If you want to make a suggestion the do it through the proper place https://twitch.uservoice.com/forums/310213-developers
Finally, the v5 API is still usable even while deprecated, or if you wish to use entirely Helix you can use pagination to count total streamers/viewers for a game yourself.