Yeasayer. All Our Cymbals was an excellent organic mishmash of a record and then they followed it up with Odd Blood with all these nasty synths and shiny beats. Saw them on the tour for the latter and the audience had changed to being full of trendy twats as well, making it all round a pretty grim experience.
Midlake possibly went the other way. I saw them supporting someone (Yo La Tengo maybe?) around the time of Van Occupanther and their support set was pretty much cut in half because it took that long to set up all the millions of keyboards they were trying to cram on stage.
They should have gone big after the steady build of that record, but then they dropped a load of the keyboards, replaced them with things like recorders and made the stinker that was The Courage of Others. They were in bigger venues than they’d ever been before touring this terrible album that killed all the momentum they spent years building.