You already partly answered that yourself. It is far fetched plot about super special agents who run private business and are able to do things on their own all American secret services aren't capable together. Caveziel's character is built like typical 80s action hero, except he's boring as hell. The other guy tries to be witty impersonating already mentioned James Spader. I'll rather watch La Femme Nikita from 90s, makes more sense.
Actually I know show that takes itself even more seriously than PoI which makes even more of a cringe fest. No it's not X-Files Season X... we don't talk about that anymore, ever again... it's Empire, gangsta show about music industry.
Maybe I'm too harsh, certain anime set the quality bar too high but shows like PoI make me laugh in a bad way. I'm more into light hearted shows with interesting plot and cool characters like Forever or Castle. Forever was such great thing to watch, always made me happy. Until assholes from Fox canceled it. Like going through that episode with Firefly wasn't bad enough already.
Edit: Took me awhile to remember of whom John Reese remind me the most. It's Steven Seagal, from Nico movies.