Andy, I think the biggest problem for BHX is that an airline can serve say Heathrow, Manchester and Edinburgh and that will cover most if not all of the UK. Consider you don't have to go very far South or North before either Heathrow or Manchester is as close as Birmingham.
As for landing fees, I'm not sure what else BHX can do. I'm not sure if it happens with all new routes, but if the landing fees (or any fees) are either waived or discounted for the first year of operation as an incentive for an airline to start, by their very nature those fees will have to increase after whatever that introductory period was (say 12 months).
The idea about reduced fees for a year is partly to incentivise airlines to start new routes, but then after a year of operation the route will have grown to the extent that the reduced fees are no longer required. In the case of Birmingham, the passenger numbers and/or yields haven't grown enough so that the airline can make a profit when the fees increase to their normal level.
If you were to lengthen the time that the fees are reduced, you couldn't do it just for one airline but you'd have to do it for all airlines - that might not be financially possible for the likes of BHX.
It's not secret that airlines don't make much profit per passenger - I believe easyJet is less than £1 per passenger.
Not that it's likely to happen, but the best chance that BHX has for its long haul ambitions is for one of its currently based airlines to launch long haul. Jet2 seem to be favourite to do that, but that's far from certain. Even if they were, its highly unlikely they'd fly any routes East.
The airline business is completely crazy! Emirates cancelled its initial order for A350s to order 787-10s from Boeing, but is now considering cancelling this order in favour of 777Xs and reinstating the A350 order with Airbus instead of A380s .........
If I tried doing this with orders from a trader I'd surely be banned from wasting their time in the future.
The thing is airlines pit one manufacturer against the other to get the best deal from them. Also with airlines as large as Emirates, an order can represent a large amount of that manufacturer's 'income' for that year.
Consider that Emirates operates/order for:
-B777X account for 46% of all B777X orders
-A380 account for 50% of all A380 orders