It’s not necessarily trouble, he is doing a job, and an ok one, he really is. He’s not as quick over the toms or as intricate (Brain drums as well with his feet as he does with his hands, his pedal work is fantastic)
Of course he is keeping time in a live setting, but he is not playing the parts ‘effortlessly’ the same as Matt was not doing so with Stevens parts.
Frank imo is prob like a Matt Sorum level, decent.
But Brain could probably fill in for most bands. I would also take Matt back in a heartbeat.