Well being that Universal have spent a shit load of money to have a HP themed land, I doubt you'll see any more HP than what we already have. Put simply - WB holds the movie licensing, and Universal the theme park licensing - shit - we might as well lobby MW to replace LTRR with Pirates of the Carribbean!
Matrix is dead. It was a cult followed franchise, but it's over. it has no lastability in todays market. The matrix exhibit was shit.. and boring. A walk through attraction that isn't worth the re-rideability, and therefore, regulars avoid it like the plague. I saw it once - that was enough. To announce an attraction NOW based on a franchise that had it's day THAT LONG ago, is akin to MW announcing a new Lethal Weapon roller coaster - it's not going to happen.
Themes have to be current AT THE TIME OF CONSTRUCTION - unless - UNLESS that theme has long standing. The DC characters have that long standing - so does Scooby Doo, and so do the WB characters. Even the AVPX has a theme that has stood the test of several decades. And police academy - whilst it was getting on in years - had movies that also spanned two decades (or was it three?)
Look at Wild Wild West Adventure Ride - themed to capitalise on the movie, and dumped once it lost its relevance. Cartoon network made way for nickelodeon... nickelodeon made way for Dreamworks. I'll bet with the demise of the wiggles that we'll see that disappear with it's lost relevance once the 'new wiggles' die in the arse (which they will).
I'm all for the park expanding, and opening a new themed land with some great new attractions - problems include a lack of space to the back of the park due to the backyard neighbours (thereby requiring any expansion that way to be 'indoors' which also loses a key access route around the back of the park too). Expanding to the front has been done about as far as they can, which is why we're seeing replacements instead of new installations (GL excepted). I'd like to see them utilise the land between the sound stage and WWF, and they probably will someday - by which time franchises like the Matrix will long have been forgotten. HP will live on but only because of the fan following, and the kick ass themed lands made by universal - we won't see that install into MW.
Dare I say - something still current, recent, and easily themable would be Twilight - but I hope I don't get banned for swearing... not to mention that i'd probably avoid the park like the plague if they did something like that.