But yeah, that'd be possible enough.
Maybe not as fun as a big Doctor Who party, but fun.
Wouldn't be that hard to pull off in theory, but you'd have to make it entertaining and original, so as a filmmaker you'd just have to be really creative and funny and clever. Which is always an enjoyable problem to solve. =D
It would be more fun to recut Arnold movies into chick flicks. Romantic comedies, swooning epic romances.
Like that trailer for The Shining.
EDIT: Actually, to give your "best of Arnold" film a different feel if people watching it are really familiar with lesser Arnold films, you should create a new villain for it. Steal a villain from some other, non Arnold film. Villain scenes are usually separate from hero scenes anyway - they're off in their office or lair plotting and don't meet the hero til the end. It's the lackeys who Arnold has to shoot and blow up. I was gonna say, take a villain from some lame action movie starring a lesser hero, but hey, go for broke, make sure it's a good villain ... like, someone like Christopher Walken or Robert Loggia or Frank Langella or Ian MacShane or Dennis Hopper or Hopkins. Anthony Hopkins.
Sylvester Stallone would be hilarious for stunt casting (Get Carter remake era, Spy Kids 3 type) ... but probably for no other reason.
If you were a Hollywood director and could film new footage for this, my casting suggestion would be: Dolly Parton.
I'm gonna keep quietly suggesting the "Crawford redub" Phantom of the Opera and extended Muppet Movie as edits, since someone oughtta do 'em.
Redub Phantom would be a huge hit.