If you're going for fluffy/storyline, then this works. One of the biggest reasons you don't see people using those shrieker cannons is, it's simply not efficient for the points cost. You're paying for a melee unit, then paying a premium to add a ranged model. Then, on top of that, their 5+ saves aren't too reliable, and they're slow(being footsloggers). You pay 100 points for that.
You can get the same thing for 61 points, with objective secured, from taking eldar allies with windrider jetbikes. They can get a shuriken cannon, have a 3+ armor save, the ability to jink, and can move up to 48" in a round.
Secondly, I'm never really a fan of putting single blasters into warrior squads. It's just not efficient. You end up wasting a 15 point blaster shot, or 4 splinter rifle shots far too often. If you take them all off your warriors, that gives you 60 points. If you drop the wracks and their venom, you're up to 155.
7 Wyches with haywire grenades in a raider with enhanced aethersails and TGL is 154, and a far more reliable way to get rid of vehicles than having a single blaster in all your warrior squads.