I think a big criticism of S1 for me is that a lot of big important things happened to JLP off-screen and we're just told about it. Mainly, the whole thing with his deep connections and work with the Romulans. Apparently in the time in between the events of NEM and PIC S1 we are asked to believe that JLP developed a very strong bond with the Romulan people and affinity for their culture and Starfleet's handling of their plight made him jaded...which, ok, I guess....but it would've been more interesting to SEE this bond being developed and drive the events of the season. His conversation with the nasty admiral would've been better if HE was the one saying "sheer fucking hubris" to HER about Starfleet's handling of the crisis. There are other choices they could have made, though not without their own challenges. JLP had an affinity for the Bajorans, but Sisko is the one who really took up this mantle, and then of course the most obvious choice is the Klingons, but this would've been hard to do without a beat-for-beat retelling of the TNG episodes about this.
It was hard for me to be invested in the Romulan stuff because it was all just out of nowhere or obliquely referred to in other things without being something that made sense for JLP. I do give them credit for dealing with the out-of-universe decision to blow up the Romulan sun, which would of course have massive repercussions in-universe.