Agreed there are epic revamps going on at the moment in all the terminals splashing a fair amount of money about.
What would improve the passenger experience both immediately & relatively cheaply, would be the small things.
Why is it so many escalators, walkways & lifts do not work? Why have there been queues of over 100 on the ground floor T1 trying to get to check in on level 5?
Why was a lift in T2 multi storey u/s for six months?
Why was it one day all 3 lifts at the rail station were u/s ?
Why are the toilets often dirty & smelly.
These are simple easy things to fix that have a big impact on the customer.
... and yes, I agree, stop fannying about with other airports & fix this one.