It's absurd to compare the two versions of the character, but what he means is Kratos was never intended to be overwritten like he is in the 2018 and it's very obvious.
It's actually funny that they took a character like that and turned it into a family drama tv show. It's almost as if Nintendo had done the same with Mario. Obviously even young Kratos is more fleshed out than Mario, there was already a scenario in the first trilogy, but still you get the idea. It's in that sense that he's saying it should have been a new IP, because it's so bizarre and out of place.
Only the writers of Lost Planet 3 could have achieved such a feat. Take a 2000's edgy character so seriously, to the point he indulges in so much guilt and self-flagellation. It's really ridiculous to me but objectively they succeeded given the critical and commercial reception.