No support, this would cause many issues. There would be gigantic mega-plots everywhere, huge. I think having a 4x4 plot is just fine. And like Muse said above, there would be arguments among players if they want to unlink. Not only this, but more lag than there already is. This is a huge plugin, and I personally believe that all the merging is causing tremendous lag for creative, and just giving people access to make even BIGGER ones would just cause to many things for creative and it's community.
And I'm not being rude to some players, but most plots are blank, inactive, a few blocks placed, would a few bigger plots make that much of a difference since most players hang out in role play plots and clubs?
Support... But there needs to be a way to be able to disconnect the plots on both sides consent if e.g. you're done with the build and you want to have your own plot back.
Since the paths are 7 blocks wide, consider only building terrain on pathway sections to make life easier if someone wants to un-merge. That way you know you won't loose your bigger builds.