They really need to get on it. Remake the first two games in the same vein as the Crash and Spyro remakes. Rework some of the more clunky/outdated controls (flying, swimming) and subtly fix some of the issues in Tooie by making things a bit clearer. Sell it for $40 or so and it would do really good.
People shouldn't act like the HD remasters are reasons why Microsoft shouldn't do this. Those remasters were good, but they were just n64 games running at 720/1080p with like, 1 or 2 gameplay enhancements/changes (saving music note total when leaving level, stop and swap). They weren't advertised nearly as much as a full on remake would be, and they were digital only (I guess bundled with rare replay too). Anyone who would seriously argue that a Digital only, upressed 1080p ps1 Crash 1-3 collection would have sold as much as the N-Sane trilogy is straight up wrong.
A lot of the enviornments and models in the game are just begging to be remade too. I'd love to see Glitter Gulch Mine, Click Clock Wood, Witchyworld, and Mad Monsters Mansion remade for current, or even next gen tech depending on when it would get greenlit and how long it would take to develop.