3 car teams seem inevitable, it's only a matter of time until the smaller teams will fold under increasing pressure, without a cost cap they are doomed but while there are vast powerhouses such as Ferrari and Red Bull with massive resources cost caps will always be vetoed.
Pay drivers are a blight on F1, if a team needs to bring one on board then they have to 1st prove themselves quick and capable in the junior series. To make it more financially viable more media coverage will be needed in the 2nd tier of F1 to increase audience numbers and in return more sponsorship deals for the drivers in question.
I believe the next evolution of GP2 cars is due either next season or the one after, this would be a perfect opportunity to make that series closer to the speed of F1 which should help find the best of the junior talent and make them more attractive to the F1 teams.