That would certainly be very interesting and add variety to the magazine. I just think the editor (is it going to be you, then?) has too keep in mind that the less text the better. People often skip blocks of walls. I tried making a "storybook-like" comic once and still I think there is too much text, though I cut off everything unnecessary: http://tapastic.com/episode/226318 (it has two parts)
Also, I would suggest limiting the "recommendations" only to short info about what specific aspects of the comic the person recommending it finds the most interesting / unique, and why they think more people should read it. Otherwise I fear you would get a pile of shouts like "Go read Gaming Cat, it's cool" or "Emo Brat is just too funny", etc. , which are useless to the purpose because the reader doesn't get any info from that, and also everybody already knows these comics. Or people would be recommending comics of their friends just because they're their friends, no matter the comic quality. I would direct it to the goal of promoting not well-known comics that are unique.
IMO, a mix of all these things would be the most interesting.
That should be very interesting to creators as a way to promote their works, but would need to be directed well - like a preview of the comic customized only for the magazine, or a short comic going by the issue's theme (eg. Christmas) while featuring characters from the artist's series. Chunks of comics just for the sake of promotion should be avoided.
I can't see any disadvantage the magazine would be getting from a comic in the issue being simultaneously posted on the artist's series. I believe there are only benefits to that. I don't think people would unsub from the magazine if they see one of the comics in the artist's series they already follow - they would be missing out on other comics that will be in the issue but that they're not subbed to.
Personally, I would be less interested in the project if it was on another website. I may be biased because I'm a person that basically lurks only on Tap, but seeing how people were unwilling to move to Patreon with the end of Support Program, I doubt I'm the only one thinking that. I'm sure there are always ways to do it on Tap, they just need careful consideration.
Sorry if I sound a bit negative, I'm a pessimist, I guess, so I'm good at pointing out weak points in plans 