It's unusual for WGN to decline in baseball season, as they usually increase, particularly in 25-54. But they have not done that this year.
Well, it's also unusual for the Cubbies to be as bad as they've been during the early going this year.

Back to the other point about Merlin....not only is WIQI losing to Merlin's revival of the format they ditched for their low-power signal, but their numbers are also worse than what was on the low-powered signal ("smooth jazz") before Merlin took it over.
On top of that, they're getting beat by the WCPT Lib-talk AM and rimshot FM combo....along with a few other rimshots, religious, etc.