I was also pretty much a D.Va one trick for many seasons, season 3 until around Goats where she could obviously still be run but where a good Rein or zarya was more important so I'd rather play those. Since 2-2-2 she has been trash and I only ever play there if necessary to counter a carry on the enemy team.@Wegason used to one trick Dva back when she was a must pick but she is an ult battery nowadays. I was doing pretty well solo queuing hit 2960ish from placing about 2750 and now it's bad game after bad game. Only way is up now tho right?
One of my continuing frustrations is people who just don't switch once they've locked in. I personally switch hero whenever I feel my hero isn't working or we need something else. So many don't though.