I like the speculation about MBr versus CCr. Lets have a bit of analysis (tech crap follows)!
1. The code for both games is in 6809 assembly. This is a very verbose "language" that new software engineers don't really know at all.
2. If they were to make Cactus Canyon, the gold standard is epthegeek 's Continued software. Reimplementing the same features in ASM6809 is borderline impossible using the original code alone. That means that the modifications have to take place downstream (in the emulator). CGC uses stock roms for most every bit of emulation.
3. When you're making improvements in emulation, you really can't change a lot of the original code's behavior, BUT you can jump around it. This is generally used for things like debadging the game of any Williams logos on the DMD, coloring the dots and timing adjustments. Even with the advantages emulation gives you, writing new game modes in this way takes a lot of time, and for half of the modes that EP implemented in Continued, that would have to happen on the original game code.
So given the above technical factors, and given the fact that the talent pool at CGC has changed, I'd put my money on the next remake NOT being Cactus Canyon since it requires quite a bit of legwork for the product to work on any gameplay feature set compared to what already exists out there.