The plans cover a lot of the needed issues:
Full length taxiways and high speed exits - they will improve safety and efficiency, reducing delays, pollution, costs and missed approaches;
Improved road access - need I say more?
Increase numbers of stands;
Increased departure lounge space and shops;
Improved security area;
Improved short term parking.
What hasn't been mentioned is doing anything about the embarrassingly shabby arrivals/immigration/baggage reclaim areas and the appalling walkways and "bike shacks" for stands 1L-10. The halls need more than a refurbishment and proper buildings need to replace the octogon and white shed, and weatherproof corridors to each stand should be built so that passengers don't have to be exposed to winter weather while waiting for boarding on stands 1-4. There also needs to be a passage from the new extended departure lounge to near Bar 10 to avoid the ridiculously long walk currently needed to the main apron gates.
It would also be handy if the airport ops department would get the bizjet operators to improve their efficiency - they are so bad for traffic flow with their slow taxying, slow back-tracks or vacating, gash RT clogging frequencies, un-necessary full-length departures and sloppy arrival planning needing extended track miles and getting in the way of commercial aircraft. I wouldn't want to see them pushed away as they're a big financial asset to the airport and area, but they need to be less disruptive to other operators.