Let's be honest the half time shows are almost always going to stink. It's super commercial pay checks for established acts driven by the corporate sponsors who drop millions of dollars to put them on.
Occasionally that's going to cross over with actual interesting and memorable artists and you will get stuff like Prince or even Bruno Mars, but that's more coincidence than anything else. They are shooting for super safe, "hey maybe your grandma has heard this on the radio" when they book these. Not sure what you guys are neccisarily expecting.