I think that while he was liked in the Shield, without it, he lost a lot about his character that worked. Now he looks like a guy who is trying to leech on the Shield. He has the "Believe that" catchphrase, instead of being a Hound of Justice he is the Big Dog, same theme, and attire, etc. Plus, Seth and Dean did stuff different with their gimmicks and presentation to build themselves on their own. The Authorities' poster-boy with Seth and the Lunatic Fringe with Dean. Not to mention Seth and Dean waited a bit before they were thrust to the main event and had a lot of time to develop. Dean was an IC Champ before winning the WWE title, Seth was Mr. MITB for a long while and was a center-piece of Raw and used the time to prove himself as a major part of the show, Roman didn't do those things and he even missed like four months due to injury. And, they didn't change plans with his injury and this was around the time Daniel Bryan came back and the fans, who wanted him in the Rumble last year and were sad over him not being able to see his title reign through, wanted to see him rise again in a literal Dream Match at Mania between him and Brock Lesnar of Beast vs Underdog (or Goat). All this spelled disaster for Roman at the Royal Rumble and we've been salty ever since.
