Deepbit had controlling share in the network a couple of times and we survived. They won't do anything because it's in their best interest to play nice. Think about it a minute. They're holding a mass of btc profit from running a successful pool. They could continue making more money but instead they decide to make their holdings worthless by fucking with the network. Yeah, that makes sense. Calm down people, the sky isn't falling.
Their "mass of BTC profit" isn't from their pool. Their pool costs them money, it makes them nothing. It has, from day 1, made absolutely no economic sense for their pool to exist at all. Their private farm is as large or larger than any other pool as is, so the argument of letting others join them to reduce their variance is moot. They're too large for variance to make an impact on their monthly revenues. They're paying to run servers for people for nothing, unless they're skimming from the top.
We have no idea what their business model is but it does make sense to lower their variance by allowing people to hop on their large private farm. Or their game plan might be to remove the competition (such as yourself) by stealing as many customers as possible and then creating a fee that is profitable. Skimming is very possible and, as you know, has been done many times before.
Creating fear isn't going to change anything. Removing the PoW system and moving to Proof of Stake can fix the problem for good. But we can't change our beloved Bitcoin can we? Heaven forbid we fix basic design flaws like the PoW system or prune the fucking blockchain. That would be just awful. /endrant