I just think moderation is a good idea. Mounted Marauders looks like a good card, one that will make Chaos stronger. It's good to think ahead and anticipate problems, it's bad to overreact and call for restrictions or bans that we don't know yet are truly necessary or that might tip the balance in exactly the opposite direction - if we assume Chaos with Sorcerer of Tzeentch is the strongest faction, Chaos without the Sorcerer might not be on par with the others, but weaker. So restricting it might fix the problem only to create a new one.
Of course the restricted list remains questionable. It always will. It would look different if you wrote it, and different again if I did. Invasion is a game with many options, that leads to A LOT of different opinions. It is also a constantly evolving asymmetric game, so evaluations need to be constantly adjusted, that is its beauty and in some ways its curse. Dwarves were the top dog, then the restricted list was introduced, and some people were ready to give up on them because it hit them so hard. But it looks like they're still doing just fine. Now it looks to some as if Chaos is pulling ahead, but we don't know if it really will, and if it does, if it'll be to an extent that needs fixing through restrictions or bans (by that I mean that true balance cannot be achieved in a game like Invasion, and it's quite all right if factions take turns at the top spot).
Opinions differ of course, but for me and some others I can say that the increased activity here we saw from the "petitions" was not the kind of activity we enjoyed. It's great if people post here a lot, but if it's mostly in a bitter, vicious or self-righteous tone, or if there's nothing new, just the endless repetition of arguments already made plenty of times, it can actually turn people off. From the forums and the game.