#1 Lana
This one takes the cake on baffling gimmick changes. When Lana debuted in WWE as Rusev's manager, she was portrayed as a strong, dominant female who was the only one that could control Rusev. Her aggressive, take-control "Rusev, Crush" was part of what made Rusev and Lana such good heels.
The fans supported her, chanted her name every time she appeared but for some reason WWE decided to make Lana softer and started a romantic storyline with Rusev. Yes, this was partially due to Total Divas as Rusev and Lana were getting married and WWE wanted to cash in on that storyline but this effectively killed Lana's buzz as a devious heel.
After some inept rivalries with Roman Reigns and Enzo Amore, a stale storyline of tension between the couple, and Dolph Ziggler stepping in as a romantic interest, even WWE decided that there wasn't much to be achieved by keeping Rusev and Lana together. So, WWE decided to launch Lana as a solo competitor.
This wouldn't have been such a bad idea, if Lana hadn't adapted a Summer Rae gimmick of being sexy, sultry but not a very good wrestler. All in all, WWE rushed to hype Lana, not giving her enough time to train to be a better wrestler and eradicating the only thing that was getting her over with the fans, her gimmick as a compelling, authoritative, unsubmissive heel.