Slides are unsafe unless you incorporate spacing. Plus crouching medium kick is one of the best ways to setup v-trigger.
Crouching heavy kick isn't bad either as an anti-fireball if you want to get a crush counter to setup for a fireball crossup.
sim is still keepaway, but he has enough tools now to incorporate some silly rushdown-esque shenanigans, which helps since his v-trigger is most effective if you've almost put them into the corner. slides are an important part of it, since they're typically good for, in order of light to heavy, positioning against jump ins, setting up the v-trigger, and anti-fireball crush counters.