Maybe he already has one,and he really just has really skinny genetics,but I find it crazy that hes 6'7 and only 215. Hes lighter than a prime Tyson and 8 inches taller! Even if he was 225-230 he'd still be quite light for his height,so I cant imagine him losing any speed or reflexes, but he'd have that extra power for his punches,and strength for the inside when he needs it. A bit of extra muscle would add power and would help with his punch resistance when he finally needs it.
he's young, he should let the weight come naturally as he enters his prime, he will keep his speed and he has good power, id like to see him someone better, but I think his team are just running out the clock on the Klitchkos aswell...
He's got enough power for knocking over the department store mannequins he's been fighting. What he needs is someone that will fight back and not take a fall for a paycheck.
If they fight back, his glass chin will be shattered - which is exactly why his management feeds him stiff after stiff. No amount of weight training will give Wilder a solid chin. He's a KO waiting to happen, nothing more.