Presently martial attacks are generally superior to other methods of damage output (spellcasting) for several reasons. This has been compounded by AB and DMG growth, with on hit abilities and presence of divine smite builds etc.
One key difference is that a spell can be interrupted quite reliably with high damage numbers, and at most 2 can be cast per round if hasted. With high AB and APR #'s the ability to provide reliable threat against a target is much higher.
In a similar manner to how spells can be interrupted by the caster receiving damage, I suggest that martial attacks (ranged and melee) experience a debuff based on a failed check (concentration/discipline etc) such as a reduction in AB, APR or something similar. This would mean that opponents have more reliable counterplay to lower the damage output potential of a martial combatant by applying damage to them. Hard CC is basically non viable with saves where they are so it could be a decent stop-gap.