The 51% attack is very much accomplishable; just check out this video. 

https://www.youtube.com/watch?v=Kjtgp5h-jEY

This is part two of his review of the 51% attack; and I think it brings up some points that the community really needs to take seriously for the security of the future.  This isn't about conspiracy theories and 'what if' scenarios; its about building a proper foundation for the future of crypto-currency.  Issues within the system are only going to be magnified as time goes on and more and more people get on board bitcoin.

I am in no way tech savvy, and I am still learning about bitcoin so don't 'Mance Rayder' me... but bitcoin is based on a system of decentralization; what if we built some framework for mining to be accomplished in the same way? A trustless and decentralized regulatory system for the mining process. 

I'm thinking of a system that automatically chunks the power of the mining and distributes it to separate pools. Each pool is allotted a percentage of the total mining capacity and that percentage is equal to all the other pools in the system.  So let’s say a bad actor floods the market with 51% attack power, that power would be distributed to 100 pools that each have 1% of the total power in the ecosystem. Each of those pools should then have the ability to water down the voting power of one bad actor because they would have to sway 51% of the pools to gain the voting power necessary to take over the market.  I'm not sure if this would work... like I said, I'm new to this but I really want to see bitcoin succeed and I hope this could help.