Unfortunately, I disagree quite strongly.
The Veteran, even the Sharpshooter class, get grenades and a wide assortment of guns that are not restricted to single-target DPS. The Bolter, for example, has AoE on-hit. So, while they do undoubtebly have top-tier DPS, they also have decent crowd control. Is it the best crowd control? No, far from it—but they have it as part of their base-kit. The Psyker, meanwhile, has to equip a staff specifically designed for crowd control in order to compete on that front.
That’s not even taking into consideration how Brain Burst, no matter how good you say the tracking is, does not scale in damage, even at higher difficulties. So, again, a good Veteran with a Legendary Bolter will absolutely put a Psyker to shame, and usually without even trying. Their arsenal rockets past what a Psyker can do in terms of damage, meanwhile Brain Burst still requires a 1 - 2 second long cast time at the flat cost of 45 Peril, and can’t even kill Elites in less than 2 - 3 consecutive hits.
Do they have downsides, like their aim shaking when taking damage? Yeah—so does everyone, and the Psyker’s cast-time / targeting is reset when they take damage, too. So, this is an entirely moot point.
So, the long and short of my point is: As it currently stands, the Sharpshooter’s swap animation is, frankly, barely any longer than other high damage weapons, and for a class that can dominate the playing field, I don’t think this should even be a complaint to begin with.