I don't believe it's a question of investment in a control tower displacing investment in runways or taxiways as the funds for a control tower will come from the IAA but they would not be contributing to any runway development as that is for the airport itself to fund.
As for 07/25, I think it may well be a more viable option for extending, as there is plenty of land to the west. Some posters have cited the road as an obstruction but that is very easy to run beneath the extended runway. How many airports around the world have we all seen that in, and they do it for 4 lane motorways and railways...I'm sure we could manage a 2 lane backroad!? The biggest drawback is that an "extension" to 07/25 is going to cost a lot more as it's already a lot shorter, and hasn't had the pavement investment of 17/35.