I do not know much about MidWest airports but I could talk about my own POS. In the '90s there was talk about building a new terminal to replace the present structure, which dates from 1962, because it was seen to be unattractive to visitors and too small. The plan would have seen it with 8 jetways and a modular concept which could have been expanded later, plus eventually a new runway. This Project Pride flopped without ever getting off the ground.
In the last 2 years the project was revived by the new government of Trinidad and is being touted as the hub of the Caribbean. It features 14 gates with 12 jetways, many new facilities and a new postal office and catering facility (which was built before the terminal).
Now the reality; POS had a heady bit of traffic in 1999-2000 with BWIA expanding its services with a regional feeder, BWee Express, serving neighbouring islands and opening up a new service to IAD. Air Caribbean, its home-grown rival, started up regional flights too in addition to its primary domestic services and even expanded to MIA. American came twice daily, Air Canada a few times weekly and other smaller regional carriers made their presences felt. In July 2000 came Air Jamaica from Kingston with its own expansion plans and thus, it seemed, the range of airlines here justified the new airport.
Now what has happened? Air Caribbean went under in October, Air Jamaica's Trini fling flopped and it has left POS and thus 15 daily flights have disappeared. BWIA's monopoly has become strongly established here. While POS does have a lot of O&D traffic with the large home market and the correspondingly large visiting friends and relatives market (VFR), these sectors are strongly loyal to BWIA and so the local scene is not encouraging to new airlines. There is little tourist activity in Trinidad and while some, including BWIA, insist that POS remains the hub to Tobago and hence the leisure market there justifies the new POS, the fact is that connecting in POS for TAB has always been seen as a hassle and direct flights to TAB are preferred. BA's success in TAB attests to this, alas, the small local market there has been a impediment to major expansion of airline services there.
So the new POS continues, behind schedule and with several overruns in cost and with an uncertain future. It seems as though only BW's will be lining up there, along with the AA and AC flights, while the smaller Barbados airport will see those heavies line up and stack up (I saw 4 Britannia 767s there last month at one time). In any case BGI's wider range of air services has made it the Eastern Caribbean hub of choice.
Hop to it, fly for life!