It's great for alts. You reach concordance and then you just naturally get it for doing nothing. You can literally just mission board with decent followers after you hit 52, and your alts will probably only be several traits (at most) behind your mains when 7.3 comes out. If you did this at the launch of the expansion you would probably be a dozen traits behind, or more.
For mains it literally doesn't matter either. As long as your AP bar isn't at a standstill, it's still okay to do activities that yield AP, I just wouldn't go out of your way to do them. The Top AP farmers in the world are trait 63, and have likely been doing ~8 hours worth of M+ a day since 7.2. For all that effort, trait wise they are maybe half a dozen traits ahead of people who do a single M+ a week, occasionally do emissaries, send out missions each day, and maybe hit up a couple big AP quests from time to time. Half a dozen seems like a lot, but considering that the general power increase from each individual point compared to launch, it's pretty small. That gap might have been a 6-8% power increase (or more) at launch, but now it might be a little over 1%.
The worst thing about it, at least for AP farmers is that it's only going to get worse. There is absolutely no way they can increase efficiency or put in more time to keep that gap. Eventually casual Joe who plays basically the same amount every week is going to see that gap of half a dozen shrink to probably ~2 by the time 7.3 comes out. Casual Joe probably won't have blood clots either.
For all intent and purpose that's me giving a long winded response about how the AP system is basically obsolete. It's has enough impact that you probably shouldn't ignore 52 (and honestly, several traits after 52 aren't too time consuming), but that's absolutely by design. It's basically content to keep you honest and put some effort into a character. I poop socked a lot on my Warlock once he hit 110, and it literally took ~12 hours of playtime once he hit 110 to cap get him to 52, and he's only 3 days old.