This would make tank tracks viable as right now their slow movement speed combined with pen builds being rather common on higher PS means they are just not worth it. having them block penetration of shots would make up for it.
Though to balance it I would make it so that hovers do not function on builds with anything other than light tracks.
To continue this line of thoughts I would demote light and hardened tracks to special tier and not give them the blocks penetration perk.