sounds like he is no longer interested in the case...
Perhaps he decided it was unsolvable, or got tired of conjecture/infighting. I was reading a lot on an older Cooper chat site - can't remember what it was called - but eventually abandoned it because two people in particular seemed to hijack (ha-ha) every thread screaming about their favourite suspects and there was a lot of bickering in general. This site does a better job shutting that down, thought I did see somebody ranting about Obama or Trump or Rosie or somebody the other day, and frankly if I could stand to hear about current US politics, I'd be reading about that rather than digging into a case that's almost as old as I am. I certainly didn't mean to imply Sluggo had passed on, and I'm very glad to hear he is still with us!
I do have a fave suspect myself, but try to keep an open mind. I am not overly interested in conspiracy theories; however, it is crystal clear just reading the basic documents in this case that there are either major chunks missing from even the witness interviews, or the FBI screwed up on those. So I'm also staying open to critique of the FBI investigation. (Plus, y'know. Hoover.)
I do think outside-the-box thinking is as important in this case as the rather limited evidence available. (I'm gonna start having dreams about those missing cigarette butts, not good as I'm trying to quit smoking for 2018!

) I'm glad so many are focusing on the scientific aspects of the case, as I have nothing to contribute re: the technicalities of parachuting, cartography, or dredging, for example.
But I've always been a mystery obsessive (unsolved stuff drives me batty), and I'm good at analysing little details. (Agatha Christie has only tricked me thrice in 80+ books.

For example, Tina's testimony mentions Cooper's fine mannerisms. Having seen my fave suspect on video, I am sure he possesses them; I would imagine someone "between genders" like Dayton may have as well. Eliminating suspects based on looks is a bit tricky in this guessing game (though I'm willing to eliminate Weber based on those ears - an impossible characteristic to disguise). But things like a rough way of speaking, uneducated diction, or a lack of those genteel mannerisms could perhaps eliminate some suspects.
Sorry I'm all over the board here. So much stuff! But I'm not sure the case is unsolvable, despite its labyrinthine nature. The skydiving community in 1971 was small. I'm amazed how often I've typed in a suspect's name and found them mentioned on some skydiving forum in non-Cooper-related tales. (For any skydiver who may be on here, by the way - from what heights were people doing those "batwing" type dives in 1971?)
Oh, one thing I do know a lot about: extreme temperatures. I lived in Labrador (northern Canada, just below the Far North) growing up; I lived in Vancouver, BC as an adult. Both about 16+ years. School was cancelled in Labrador at -63 to -83 degrees Celsius, windchill included. We were outdoors in the cold at -40 or lower regularly, for long periods. We did not die. Some people went out in shirtsleeves at -10 or lower. My only weather issues on the West Coast were the lack of sunlight due to the months of rain. So unless someone thinks Cooper died of Vitamin D deficiency during the jump, I'm not buying death by exposure. (Oh, by the way, science fans - don't know if anyone has mentioned it here, I'm certain someone must have by now, but just in case, remember that the calculation method for windchill changed at the turn of the millennium. Those numbers above were recorded in the old system.

)
Now, of course, jumping out of a plane into a storm is not the same as walking into one. But presuming Cooper was an experienced skydiver and didn't get hit by lightning, I do not buy that he died from exposure. The most cursory read of parachuting sites convinces me the jump was totally survivable. Landing in the woods is something else again. (This is how far this Cooper takes you in research: I actually looked up when bears hibernate in the Pacific Northwest. Late November, by the way.)
I'll end it here, sorry for babbling. Love the forum - awesome job moderating, Shutter. You all make me feel less nuts for thinking of 1971 every time someone mentions a plane. (Like that dude today who got in trouble for escaping a long delay by emergency exiting onto the wing. All I could think was, "What if there's a hijacker on board and that's why the plane's grounded, you moron?"

) Hope 2018 treats you all well.