Would be nice indeed, but I don't think it should be limited to Nintendo (although there could be a focus on them) and if it's gonna be by Omnimaga members, there should be an extra section dedicated to graphing calculator game reviews/news and discoveries.
Also making a big magazine like Nintendo Power would be a lot of work, so unless it's kept a bit smaller I doubt it would work in long terms due to lack of motivation. On the other hand, how many pages are there in a Nintendo Power magazine nowadays and how many are just an ad?
A separate calc magazine would not work, though, as it was attempted several times before and was short-lived. Examples are "Le Journal de TI-BANK", the
Omnimaga CGPN,
The Realm of Zilak (which only lasted one edition), the Calc RPG Newsletter (which did not even see one release, although an interview was already done) and the english spinoff of TI-BANK newspaper by TsukasaZX that was in development here in 2010.