For the Tactical Squad, I'd change the Combi-Melta to a Combi-Plasma because of the range, but that's more of a personal preference. Do you plan to get the squad as close as possible? Or to get it close but still sit at a reasonable range?
Also, what is the tactical for? Anti-Infantry or Anti-Vehicle? Or a hand mix of both? Because if not purely Anti-Infantry, I'd recommend changing the Heavy Bolter to a Multi-Melta or a Rocket Launcher. If more for Anti-Vehicle than anti-infantry, keeping the Combi-Melta would be a good idea, especially combined with a Multi-Melta for the Heavy Weapon, but the range may become a problem depending on how you play them.
I'd also downgrade the Power Fist on the Bikes to a Power Sword and use the 10 points to buy a Storm Bolter for the Rhino, but that also depends on how you use the Grav-Guns - Anti-Vehicle or Anti-Infantry - as well as how close you realistically want the bikes to get to the enemy.
Finally, not a change, but a question: Why 2x Dual Lightning Claws then 2x (Lightning Claw + Storm Shield)?
Looks like a fun and fairly decent list regardless of whether or not you change it, plus running support for a Knight opens up opportunities depending on what your opponents choose to focus on.