I like the theme a lot! Seems unique and fun.
Some minor nitpicks:
While patrol detachments only require two troop choices, they allow up to three. So, why not divide the one of the 10x intercessor squads into two 5x squads, rather than (I assume) using the Combat squads ability? That will give you an extra sergeant, with an extra attack and an extra astartes chainsword for the non-assault intercessors (assuming you go that route rather than split up the assault intercessors), for the same number of points. Since you went with the Whirlwind tactic, I assume you want to get them into close combat, so upping their ability by an extra attack seems like something that's both thematic and optimal. Plus, sergeants seem like more fun to paint... 🙂
It might make sense to mechanize the marines with some transports. Thematically, they need a way to keep up with the tanks. Tactically, if they're gonna be your objective grabbers then you want to get them up the board quickly. The same goes for the Bladeguard, unless I'm missing something and you intend them to serve as a counter charge unit in the rear (though that seems like an expensive option).
A bare bones impulsor is 110. Getting rid of the Guard squads would leave you with 100 points to spend (50+45+the 5 points you already have to spare). I don't think they add much, since you'll already have at least 4 MSU squads-worth of coverage from the marines and, unless I missed an errata, Spearhead detachments don't require any troops. You could drop the astropath--optional, depending on taste and whether you're including him for psychic secondaries, though I'd note his survivability is pretty limited. That would leave you with 125.
What role do the Lieutenants serve? Both are kitted for close combat but, again, without transports, it's hard for them to get up the board. Do you want one to provide CC support for your intercessors? Unless they have a clearer role, I would get rid of one of them. The Reiver costs 75 and the Primaris with neo-volkite costs 90. With the above cuts, removing the Primaris Lieutenant would leave you with 215.
If you can find another 5 points somewhere (can one of the tank-based lascannons be downgraded to something cheaper?), that would leave space for 2 Impulsors. You could divide one 5x Assault Intercessors in one, the 3x Bladeguards in the other, and place the Chaplain, remaining Lieutenant, and Judiciar with them (and/or put 1 of the 3 in with the Assault Intercessors).
With that, you now have some highly mobile infantry base that can keep up with, and support, the tanks--providing you with even more opportunities to say "tank goes brrrr" while moving your dudes up the table.