Consider that the Genesis had split screen gaming at 60fps in 1992 with the release of Sonic 2. That system had a 7.6 mhz processor and 64KB of RAM. There is zero reason Halo 5 could not have done splitscreen. 343 simply had to lower the graphical fidelity, or simulation complexity to do so. They chose not to do this. Their hands were not tied.

Alternatively splitscreen could have run at 30fps or something like that.

As for innovation, it is indeed overrated, but the desire for novelty is not. I never played Halo 5 a second time, because it's basically the same as all the other Halo games, and I'd rather play something new. That, and the story being about nothing and just not being that good.

I do not think Halo will ever be regarded as it was in its height. That's not 343's fault necessarily; that's just the way the universe works. You think Doom 4 is gonna be as big a deal as the original was?