Just a couple comments since I understand where you come from Swampprof.
You first comment about new terminal or public transport to DTW...there is no debate here if deciding between the two - new terminal. Airports get access to a decent amount of federal funding by having passenger service. So it is essential to maintain some level of passenger traffic. Let's all keep in mind...Allegiant does very well from Toledo. American may not have 100% load factors, but the station is very profitable for them. There is also no financial gain for the city/area to offer transportation to a facility across state lines where they won't profit from. HSR or whatever just doesn't make sense to DTW. Not to get too far off topic, the one thing I believe that does make sense would be to try to become the test market/launch site for Hyperloop between the main rail hubs of Toledo and Detroit. With the amount of semi traffic that current is on 75...it would be a massive economic boost to transport goods from a Toledo hub (connected to rail and sea) up to the factories in Detroit. Anyway...
A new terminal is something that is needed. The 1955 model that has been patched together through the years is a money pit. Smaller cities like Saginaw, La Crosse, etc all have newer terminals that are small but modern and efficient. I'm not talking about building a massive terminal that will see little use. I'm thinking more of a smaller/modern 4-gate facility to replace the current 9-gate terminal that would allow for easy expansion should the need arise.
Next point you mentioned you rarely fly Delta. The last time I flew Delta was probably...2002 or so. Of course that was before they assimilated Northwest and still flew here. All of my travel is on Southwest, which means I don't use TOL (though would prefer to), but they also signed my paychecks for a few years so I'm a little devoted. ;) Frontier was very close to coming in here a couple years back, but then they changed their focus from the smaller cities to poach bigger markets like Spirit has been doing. They would have been great here I think, but they want the low hanging fruit.
You experience on AA I won't speak to, but I will say the local station is extremely senior and filled with experienced people that go out of their way when able. They appreciate everyone that comes through.
Last point hit the nail on the head for this area. You prefer direct domestic flights, so that naturally puts TOL at a disadvantage right now unless you are going to Chicago, Florida or Myrtle Beach. It is nothing new. I remember back to the early 90s I think it was with former airport director John McCue. Over 10 years had passed on deregulation and passenger numbers were falling and he put it out there...use or lose it. Since that warning and over the years, Toledo which use to have nearly 50 flights day out of it has lost a lot - though not all of it is the market's fault. Consolidation really kicked this market down, but I think we've bottomed out and its up from here.
Will TOL every have a significant amount of direct domestic routes? No. However, continuing to support AA and G4 from Toledo should allow us to grow with them. Off the top of my head I think there is a market for options like...Allegiant to Fort Walton Beach, Mesa (AZ), and Las Vegas. American I think I covered plenty already that connecting into their 4 main hubs are all viable, but the order they happen will vary. Growth options out of what we have could come from anywhere. I like the arena of smaller carriers in growth mode that provide a high quality product. I also feel the eyes are on what G4 and AA do as well. If we see growth start with them (which G4 is there with MYR starting), then others will notice. The whole thing is use the service we have when you can, even though I know it isn't possible for everyone. At least the idea of driving to Detroit isn't as crazy of what I witnessed of people driving 3-hour from OKC to Dallas, and OKC is pretty well connected to most major business markets.