Crash Twinsanity changed the series by forcing titular rivals Crash and Cortex to work together instead of against each other. A true classic, Crash Twinsanity's only flaws came from some glitches and malfunctioning cutscenes, but a remaster would be able to bring the best out of Crash and Cortex's adventure.
Not all Crash games were created equal. While Crash Bash was a take on the popular party game format (Mario Party), it had some glaring issues that held it back from being a true classic. A remaster would need to change some mechanics and fix the issues holding it back from being a truly enjoyable party game experience, but one many have been hoping to see again for some time.
Crash of the Titans
Crash has taken a variety of forms over the years, but the tattooed bandicoot saw him leave the traditional console-platformer and become a straight-up action title in Crash of the Titans. The gameplay was really fun and a remake could really highlight the variety within Crash gameplay over the years.
Crash Bandicoot: The Wrath of Cortex
The Wrath of Cortex sees the series leave its home on PlayStation and be introduced to the gaming world as a whole. Crash is forced to fight a new marsupial named Crunch in the fourth game of the franchise. A remake would need to give a lot of love to the title, but it would be a fun game to revisit.