I've definitely used this phrase/expression before. I'm pretty sure I first heard it from the late Stuart Scott *Googling. Confirmed he used a variant of this* while watching SportsCenter back in the day. As an aside, now I really only watch ESPN for live sports as I find their highlight shows lacking highlights and it's mostly just talking heads vying to one-up the other in outrageous comments, but I digress. I ended up cluing the reveal as a joke as I wasn't entirely sure how to phrase it. I know I've used 49-across in puzzles before. I've never tried it but want to, although I hear it's saccharine.
Even though I have 5 theme answers (including the reveal) I don' think the grid was overly burdensome to fill or has any super-icky fill. The NE and SW corners are pretty open but I was able to make fill them pretty cleanly. I am noticing a decent amount of proper names, which I think I may overly rely on; it's potentially something for me to work on.