Breaking the Pacific Rim cycle

Not sure why you made such a long post about why there wouldn't be a cross over. I think most people know there wouldn't be one they'd just like there to be because they think it would be a fun concept. There's a big difference between some one thinking something would be cool to do and some one thinking it would happen. For instance I want there Rodan to be a badass monster in the next movie that goes toe to toe with Godzilla like in Ghidorah the 3-headed monster and comes out in a draw. That doesn't mean I think it's going to really happen but it's fun to speculate and talk about if it really did.

I don't see why you see the need to break down what people want and why it wouldn't work. Didn't you do the same thing to people talking about old toho monsters being brought in to the legendary series and look how that worked out.

I disagree; look at Freddy vs Jason or Aliens vs Predator, they haven't nothing to do with their respective individual movies, but nobody cares, all these crossovers are in an alternative universe, spin-offs, just a "What if...?"

what if they take place in alternate dimensions 

The only true thing preventing the two continuities from co-existing is the fact that Trespasser attacked San Francisco one year before Godzilla and the M.U.T.O.s battled there and the event is not referenced at all. If they somehow manage to fix the chronology of this, they may be able to set the stage for a crossover. Just because the PR kaiju come from an alien dimension and Godzilla and the M.U.T.O.s are terrestrial doesn't mean anything. Godzilla could fight the PR kaiju in order to defend his home. The Precoursers and their monsters could play a similar roleto what the many invading alien races in the Godzilla series did. For all we know, there could have been anti-Godzilla weapons built by the military (*cough* *cough* Mechagodzilla) that just didn't see action yet, which covers the fact that Godzilla was not referenced in Pacific Rim. Heck, even the scale that measures the kaiju is called the Serizawa scale. Though this was just a passing reference to the original Godzilla, imagine if they eventually connect it to Ishiro Serizawa from Godzilla 2014. Granted, I don't neccessarily think a crossover will happen, but Gareth Edwards did say after he saw Pacific Rim that he was open to the idea, so it's not totally out of the question.