Smash the Heretics!

Nice deck  Have you played with it yet? I used to run Vengeance! and The Black Sword in Mavros myself, but they got cut due to lack of space eventually. Your command game seems a little vulnerable though, especially with no Rogue Traders or Promotions.. (In a tight spot Primal Howl can make up for the lack of Void Pirates, sure.)

Do you get to use Inspirational Fervor often for its effect?

Heh, it's experimental for sure: i wanted to try cards I thought could be decent but never made the cut before.

Yes, I've played with it a few times (5-6) and I've seen it played by my friends a handful of times too.

In the end it works better than I expected when the opponent doesn't have rout effects (or Klaivex), but, as for the cards you named, I cannot draw proper conclusion because I've tested it mostly against Worr.

In theory, Inspirational Fervor is meant to punish decks that let you win FP very often (for example, Mobile Eldar) or to be able to sustain two big fights in a row on FP in the endgame: I couldn't test this because Worr is too strong on Greens so I usually leave them alone. As for the Black Sword, it's a great card with the Jump Pack if your opponent has to attack the unit to deal with it.

Vengeance I still think is too difficult to use to great effect, so it should probably be cut: if you can't protect your heavy hitter somehow you can't get solid profit from it.

Command surely is an issue; this deck tries to abuse the combat tricks to ensure Mavros can snipe every round and grab a command win on FP, but you're ceding at least 3 command victories every round.

Just to be clear, it's not a tournament deck for many reasons, the main one being that it dissolves in front of Kith.

However, a Valkyrie Pack on a Cardinis with the Bearer and Vengeance can easily prove deadly - in one of my games against Worr, we were at a point it seemed I had lost for sure: he had a lot of units amassed on a Green FP (his win con) and many cards in hand, whereas I had just a few Marines there (big, but few). One of those was the Cardinis though, which gained a Jump Pack in the combat phase and was fortified by a Clearcut Refuge; despite my opponent having a TT and playing two Barrages, the Tactical Squad managed to pull off the AoE three times (first combat round attack, bearer, second combat round) and won me the battle. Granted, my opponent had used one of his Fortresses earlier and didn't draw an additional one (otherwise I would be toast) but it was fun seeing a Cardinis withstand 7+ attacks.