Is It A Good Idea for the X-Men and The Fantastic Four to Crossover?

Hey guys.  I have been thinking about this ever since this topic has come up.  I mean you would think automatically that at one point they would want to connect these universes with a crossover film, but is it a good idea or is it a horrible idea?  I actually had a hard time deciding which side because each has its own positives and negatives.  So I decided to write down my own positives and negatives of this issue and then allow you guys to decide if it is a really good idea for this two mega franchises to soon crossover.

Pros: Always start with the pros

A Fox Marvel Cinematic Universe

This one seems obvious, but something that I could at least mention.  I know that the X-Men is its own universe alone, but the only other films are the Wolverine films and we still have to wait 3 years for the third wolverine film to come out.  Plans are in the works for a what could be a Deadpool, X-Force, Gambit, or Mystique film, but none of these have been confirmed.  It would be great to actually see some other characters connect these two and get some diversity to an X-Men universe that seems really Wolverine centric.  Don't get me wrong, Hugh Jackman as Wolverine is spectacular, but I think that First Class was amazing with out having to have Wolverine be the leader.  I just think that it would be mutually successful for both franchise to be in the same cinematic universe.

Fantastic Four is More Rounded

Fantastic Four while in my opinion is shaping up very well is seeming very questionable in many peoples eyes, but in a case where you introduce them in a world where they are connected to X-Men, it makes it easier for them to be successful.  You could still have them have them go into space and get their powers, but spin it in a way saying that it is a sped up Mutation in their genes.  I mean say that they are a mutants from space and you have a connection to the X-Men right there.  I did say that having Wolverine dilutes the X-Men, but having a side character like one of the smaller X-Men show up in the movie would be really cool and actually do a cool idea.

Cons: They will always be here

Muddled Continuity

This needs to be said.  We have a universe that has been going on for a long time and Days of Future Past is probably going to be much farther in the future than where Fantastic Four is going to start and we still have no idea where Apocalypse is going to be set on the timeline.  X-Men already has its own muddled continuity and lets say that The Fantastic Four was set in the same universe there would have to be an explanation like of they died or have the grave sight scene from the comic book kind of like a cameo for those characters, but I don't think that scene will be included in Days of Future Past.  It would just create some muddled continuity with the characters that I wouldn't want to see at all.

Money

While I believe that if these two films crossover it will be successful, but as successful as X-Men: Days of Future Past or Fantastic Four is.  I don't believe that either set of characters put in the same film will make more money at all.  That is really the only reason to cross them over is to make more money than the first.  I do believe that Captain America: The Winter Soldier won' hit the same amount of box office as The Avengers, while Thor: The Dark World and Iron Man 3 both couldn't do it.  I just don't think it would work the same way because anyone seeing a Fantastic Four film is seeing X-Men: Days of Future Past and I don't think that Fantastic Four is going to make a monumental box office.  I just don't know if the monetary gains would be similiar to the Avengers.