Something to consider with regards to this topic: What were the Spider-Man comics like when Mary Jane was written out of the titles? Remember, this has actually happened at least FOUR times that I can recall.
1. During the late 70s/early 80s when MJ rejected Peter's first marriage proposal in ASM #182, made sporatic appearances after that (I believe this period showed the first hints we see that MJ was initially afriad of marriage because of the divorce of her parents) and after ASM #193, wasn't seen again until ASM #238. While it probably was wise that Peter and MJ broke-up since their relationship was growing stale and repetitive under Len Wein, her absence forced writers to find replacement girlfriends, including having Peter once again get involved with Betty Brant (who, while seperated, was still a married woman, and although Peter did initially try to resist, he still succumbed, so yes, folks, it's still adultery). This practically turned Peter into a quasi-swinger, and none of those relationships--with the Black Cat being a possible exception (and that was more like something from Batman in more ways that one)--were not all that memorable.
2. During the Clone Saga, when Peter (who was then thought to be a clone) and MJ (who was then pregnant) moved to Portland allowing Ben Reilly to become Spider-Man. The idea behind this was to make Spidey young and single again without the stigma of divorce or killing off MJ and so Marvel figured replacement was a good idea. Of course, most know this was the very reason why the Clone Saga was not well recieved, to put it mildly.
3. ASM #13 (Vol. 2) where MJ was "killed" in a plane explosion, which not only made Peter single, but also a widower. If the idea was to try and make Peter get back on the dating scene (or hook up with Jill Stacy) this move failed completely because it not only made seem older, but also brought a real depressive mood to the series overall.
4. When they separated after the Amazing Spider-Man Annual from 2000, which of course freed Peter, but again, her absence made the comic seem as though it were lacking something. Of course, since the movie was coming up which would feature Mary Jane as a major character, in was only a matter of time before she would be brought back as a recurring character in the comics.
An absense of MJ from the comics for a FIFTH time will only confirm what history already proved--that the comics, with her gone, suffer because it leaves a hole that needs to be filled.