Some games are so perfectly built to suit their original hardware that they just can’t benefit from a remaster. I’d argue that Killer7 is one of those games. Port it to modern systems and re-release it by all means, but I think that there’s very little you could really do to it without changing some part of its core DNA.
It’s a weird, janky game, but it was weird and janky back in the day, too, not just in the hindsight of hardware limitations and outdated design sensibilities.
The first time I played it (on PS2), a year or two after launch, I could not get into it at all, and even somehow got stuck quite early in the game. A few years later I gave it another try and everything just clicked for me, including passing that tricky part without breaking a sweat. I can’t imagine what the issue was the first time around.
I don’t think it’s for everyone but it definitely has a charming kind of oddness, and a slight clumsiness that’s more endearing than irritating for people in its target audience.