It's interesting that the article says that nobody really owns the TECO Line Streetcar. Perhaps it should fall under HART totally, similar to what has happened in Portland with its streetcar's relationship with TriMet, or Dallas with DART annexing the McKinney Avenue Streetcar line and shortening its name to "M Line". Of course that brings to mind Salt Lake City as well, which built the S Line streetcar as part of their system from the start.
In the hands of a regular transit authority, I believe we would see TECO Line service increase dramatically. Gone would be the 12 Noon start of service that totally ignores morning rush hour and late morning travel, and it would become more valuable to everyone. The fact that the article uses the adjective "struggling" in the first sentence is because that is how its operators have chosen to run it.
Extending the existing TECO Line into the downtown core would be helpful too. As to what form it should take, it can continue as a feeder line if modern light rail progresses in the area, or it can be part of such a line with easy conversion.