Hmm...I'm not sure it would work as DMC1 is a completely different beast from a different time. It was a lot slower paced for that was part of its general aesthetic as it was born from the horror based RE franchise.
Whereas DMC5 is very streamlined, they completely removed all the puzzles from the previous game (I didn't even notice until somebody pointed that out to me) and in general is much faster paced.
As a result, methinks that Capcom want to cater to want fans want which I'd reckon would be more of DMC5 style. The reason RE2 Remake worked so much was that people wanted a return to the roots but I doubt that many people would want to go back to DMC1. And at that point, if you're basically having to change the entire game, you might as well be better off just making a DMC6 as that would probably be a better investment. Just my two cents.