The fact that it has another piece of matter revolving around its gravitational pull doesn't make it a planet.
If Kate Moss was hovering in Space outside the distance of Pluto, she could have a very fattening keylme pie revolving around her but she'd still be moving around the Sun and I wouldn't call her a planet.
She's not a planet. She's a STAR, yes ...
Pluto is midget wrestling. Interesting, but nobody at NASA is aiming any missions that direction.
Planet needs to have a singular influence in size, interest and solar system fun ... ness ... to warrant our care.
The outer gas giants annoy us enough. OK Neptune ... you are a coagulation of ammonia and sulferous and nitrous oxide .... We're not going to make a movie about you housing a tribe of beautiful women wearing swimsuit uniforms and sporting perfectly cone shaped breasts.
That will likely change. Funding for this is proceeding, after having been cancelled once and then brought back to life.