Maybe it's clear to native speakers, but both "pacing" and "frontier" have multiple meanings. "Pace" as a verb means literally just walking, as a noun it's the speed at which something progresses. So I'm not sure that everyone reading this phrase will immediately realize that "pace" actually means slowing down the pace of development (having "slow" in the phrase would have probably sounded too negative). Also, it's not immediately intuitive that "frontier" refers to frontier AI models.

Actually, when I first read "pacing the frontier", the first thing that came to my mind was a border guard patrolling a border by foot...