For both of these, Potential is not Kinetic. Boyega is VERY inexperienced and it is very clear that without firm direction he has problems being a block of wood. Case in point, pacific Rim and HOLY SHIT this movie.
In Force Awakens, he could sell having that panic attack, he could sell battling off against Kylo, and hell before the absolute idiocy of Rose Tico he could SELL sacrificing himself to take down the battering ram cannon. The issue is not potential, as his selling of these scenes shows he has that, its of experience and learned skill that he is found lacking.
Give him a solid script with solid direction, or another decade of experience under at least PASSABLE writers and directors, and he could likely pump out very solid work.