Not completely new -- I certainly recall seeing it in May/June -- but (I believe) a little 'firmer' than it used to be. It fits with what we've been reading in this thread and elsewhere these past couple of years: the banks are trying harder to spot and exclude churners, so it probably pays to be a little less aggressive. Better to get two or three approvals a year, with good or great bonus offers, than overdo it and ultimately have fewer successes.
2 or 3 a year? I'm working very hard at keeping to 6/6, instead of my 8/6 from years past. 2/3 in 12 is a starvation diet for miles and points folks. At 6/6 I'm having no problem with getting approvals for cards that don't have 5/24 or 1/24 TCs.