#2 Rusev
Rusev is currently one of the most underrated superstars in WWE. Despite being so high with fans, he never ever truly has received a spotlight that he should have. In fact, in his WWE career, he has lost most of his feuds, not to mention the recent one with Randy Orton.
Rusev has been with WWE for straight eight years, and in due course of the time, he has only won the U.S Championship (just two-times). Also, for most of his career, he's either been seen in the low or mid-card only.
The reason why Rusev might not get inducted into WWE HOF, he's never been into the main-event picture for a long time, has never done something HOF worthy and also has never ever held the WWE championships other than the U.S title.
I guess, despite being so popular with fans, thanks to the Rusev Day gimmick, Rusev might never reach to the top of the WWE and will always be seen just as a mid-carder.