That is true - even the main antagonists' motivation comes down to "connection" (the writers favourite word). On one hand I like this - people care more about the ones immediately around them, to the point of letting the whole world go to shit over it. It feels more personal than political goals or pure revenge as motivation. On the other hand - both these relationships are undercooked at best, and the sci-fi twist - resurrecting the dead, or travelling to a parallel universe to the partner - edges very hard on my suspension of disbelief.The Moll/La'k dynamic in particular is reminding me more and more of Ruon Tarka's (potentially platonic) romance with his "friend." Moll is willing to let the galaxy burn to be reunited with her love, just like he was.
I do however very much like the Breen as antagonists. Yeah, the power scale is way off, and they're not very deep developed. However I think they come across very well as pretty mean guys, no-nonsense attitude, with a clear goal, but not immediately go to galactic war or cartoonish over-the-top villainy. I think they work pretty good as the "evil" threat in the background, like the Nazis or Soviets in Indiana Jones, or the Klingons on TOS & the Romulans & Cardassians on TNG.