i'm sure he has his supporters in the Writers' room but it is probably the actor and his agent pushing for the sub plot angle. Actors are vain, self important people. They look at a script, think I don't have enough lines, persistently complain and annoy the powers that be (showrunners, writers) until the PTB give in and give him a subplot that totally has NOTHING to do with the show premise.
Make James her boss and get rid of Snapper Carr, who is just there for name recognition. He is not even anything like the Snapper from the comics. that way, they properly increase Melissa's screentime back to where it should and still give Mehcad enough screentime.
As for Tim's list, I like neal mcdonough, but a little goes a long way, and the current storyline in LoT is veering back towards 1st season, Legion of Doom is becoming the 2nd season's version of the 1st season's Vandal/Hawks.
Furthermore, I dislike Eobard Thawne. He is probably an OK actor but every time i see him I think of Tom Cavanaugh, and this new guy is a pale imitation of Tom.
So I pick Guardian and Dahrk as the most awful subplots.