I haven't heard anything about the Parsons going senior next year. If they don't have to I would, if I was their coach, advise against it. Why not get the experience of being a top dog before you age up to where you will be middle of the pack? YMMV of course.
I believe Michael will turn 21 in March; that would age him out juniors, so they would have to move up. They do run the risk of being the middle of the pack at the national level. However, it depends what your goals are. I see that things could open up greatly post-2018. So the Parsons could just focus on solid placements in the GP and elsewhere.
The Shibutanis, for example, benefited from a pretty depleted field post 2010 Olympics. Bates and Samuelson were out due to injury (and later break up) and Belbin/Agosto retired.
I don't think the field will be as depleted post-2018 but I think the bottleneck would be loosened up somewhat. The only top team I see post-2018 is Hawayek and Baker, but who knows.