The fourth season format was good. But the episodes themselves were a little too much fanwank for me.
That's been a huge problem with Star Trek since even TMP, which wasn't a reboot but assumed people were familiar with the crew and ship and wanted to see 5 minutes of spinning around the new (glorious) model. TWOK brought back Khan. TSFS made a few references to old Trek, TFF felt like a TOS episode, etc. TNG did it a few times as well in the first season, and the entire premise of Voyager feels like a return to the golden age of Trek. Same with Enterprise. And now with the reboot. Trek has been riding on nostalgia for a long, long time.
Mind you, this isn't unique to Star Trek. The SW prequels and the 2014 Rebels series rely quite a bit on the original trilogy. Same with a lot of franchises.
What's interesting to me is the Japanese format for tv shows and anime, who typically (read: mostly, not always) run for a single season or half-season, then move on to another story/universe entirely.
Especially the Klingon plague episodes.
Yeah. I never felt the change in appearance needed an in-universe explanation. For what it's worth, however, it was well done.