I can tell you some thinks from the Nurgle Rotters side of Chaos
The Rotters are a in my opinion totally different to play. A Chaos Warrior with ST4 AG3 and MA5 is good Ballcarrier and will also Level up with Touchdowns. Rotters with ST4 AG2 and MA4 are more or less like better Black-Orcs. They need Block first and then you have to go the bashy way if you get a double

no other opinion makes sense. FA is nice but in about 25 games playing them in friendlies and Liga I´ve not often seen a 1 on a FA-dice-roll, of corse not on the importent ones.
Other thinks: with no Apo your Team will suffer more then other Teams. Beastman will die and you can´t do something about it. Sometimes you must play even more safe then Chaos has to do.
Your team will level up very slow so you need a long-term-leage to be really competitive. I have a really good statistic with them with 18/3/1 on friendlies and 2/0/1 in our Leage.
Your Beastman are the really heros in a Rotters Team and you have 2 keep them alive by playing in a safe way, let the other Team playing bashy with your Rotters and your Beast of Nurgle but dont think you can win a bashing game without Block just because a lot of ST4 Players.
What really sucks if you play against Amazones at the beginning like I did in our Leage, bringing them down only on a 6 without also falling down on the Blocksymbol and 4 Block/Dodge Blitzers from the beginning, 4 Rerolls and a Apo means normally you can just hope that Nuffle blessed your dices

But if your team has enough time it can be a lot more powerfull then a "normal" chaosteam with Regeneration and Foul Apearance from the beginning for the Rotters.
mfg Bernd