I was also trying to figure out why I didn't like this film as much as the 1987 incarnation of the story (which is some very pulpy schlock at times), and here are two specifics -

1. Lack of the Villain's Perspective - In the 1987 Running Man, we get a much more "behind the scenes" look at the show's production, and with it, the satisfying slow burn of watching the show-runner squirm as he slowly loses control of his creation (who was brilliantly played by Richard Dawson, an actual fucking game show host). That being missing from the story really hurts it.
2. Ultraprocessed Action Hero Syndrome - I've never seen much of Glen Powell in anything else, but there was something missing in his version of Ben Richards that kept me from buying into the character as anything more than a super generic action hero guy (not that this is his fault, could have been writing or direction).