It's possible, that this is the year of the sales tax. Increases are being discussed all over the country and the most recent I've heard of that we'll be following on election night is proposition M in St. Louis. Half of the sales tax would go to transit operations in the region while the other half would go to expansion. If passed, this means that St. Louis will now be looking to expand its network to the plan below.
You can find studies for the six corridors here.
North Corridor is the top green line to the furthest right
South Corridor is the bottom green line to the furthest right
Daniel Boone is the furthest left
Those are the three likely to be funded first and would really improve the ridership of this system drastically. At some points they are getting to 88,000 riders a day. That's pretty good for such a small system.