I agree with this to a degree,
But I propose having a separate MS that cost more coins but is toggle-able, as I feel this would wreck the economy having the regular MS be toggle-able, as well as really putting a damper on purchases of coins which keep the server going. The regular hardcore players would still buy the regular MS for pokedollars as they will utilize all 30 days and for the cheaper price were as us regular working adults would get more value out of the toggle ms!
Say have a 30 day toggle-able MS cost 300 coins. As a working adult I would buy this ever time as I can only play a day or so a week if that. And take breaks often as Im also in school full time.
So I totally think this would be viable but only if it costs much more Coins as the server cant run for free.