The problem with this is that if you're reinvesting profits funneled through a small number of individuals, it isn't exactly a DAC anymore, and you start having more of the problems you have with traditional centralized structures. Funneling the profits through the delegates who are elected by stakeholders I think mostly solves this, but I don't see a need to artificially fix the percentage of transaction fees available to them for profit and reinvestment in the success of the network.
Why not just let all delegates keep as much of the fee from their blocks as they want, and destroy the rest? If they abuse that, they'll be voted out quickly, and the market will naturally regulate the dividend rate and strategies for reinvestment.