SEC has replaced ten coaches the last two seasons and went 6-7 in bowl games last season. Mullen was hired away by Florida, so it's really nine. ACC replaced five, going 9-3 in bowl games last season. Jimbo was hired away by TAMU, so it's really four.
Nonetheless, if the "experts" haven't realized the fact that the SEC is down by now, which they haven't because two SEC teams are in the playoff, I don't think the story for the SEC is a negative one if those two games are lost. There's going to be the "but they got two teams in the playoff" argument in its favor regardless. A lot depends on performance in bowl games this time around, but even that may not make much of a difference.
ACC is 4-5 against the SEC this season and 8-9 against the P5. SEC is 6-9 against the P5. Only meaningful games I recall between the ACC and SEC were Clemson's wins over Auburn and SoCar and State's loss to SoCar. Maybe UL's win over UK belongs in there, but considering FSU's season, its loss to Alabama does not.
Seems like the SEC is annually given the top spot simply because of the greater # of players it puts into the NFL every year. That's obviously very impressive, but not determinative of the best conference imo.