I think the Pox Renovator's ability: renovate, fits into the FW play style vary well. There are some notiable beast in FW like: Boneshredder, Death Harvester, Pox Renovator, Umbral Wulf (now a small unit), and Utterdark Voidhowler. I would really enjoying seeing an FW unit with boost beast 2 and more ichor beasts, i think beasts have potential in all factions.
For now, I think it would be best to play FW Beasts in a split with one of the more pronounced Beast factions. KF, ST, and SL all offer tons of Beast support; I would probably go with a death benefit/cheap meat build, utilizing the efficiency of Bird, Howler, and Boneshredder along with Boost and other supporting units from one of the aforementioned factions.
I really dont think we need to add more themes into FW at the moment. We have a lot of themes and some of said themes still has quite a bit of work to be really worht playing in a FF setting. (Especially Creeps and Vampires)
I would direct you to UD. I'd have to put the deck back together, but I was having a decent amount of success with a FW/UD beast hybrid; Umbrals, Grundels, Bunny Lord, Grekin. It ran a tiny sub-theme skele module (Sadly no skele beasts with boost ) that offered a bit of range, and it syngergized surprisingly well.
