...and allow powers to reduce that. I made a thread about giving powers the ability to affect the maximum hit chance. This is the natural inverse of that thread, letting powers have that same influence over the other extreme of hit chances.
Basically, the idea is we increase the minimum chance to hit from its current 5%, to something higher. Let's say 15%. Then, we give the powers system the ability to modify that minimum tohit chance, a pair of new stats I'm going to call Bolstering and Precision. Bolstering would modify the minimum hit chance of tohit rolls against an entity, while Precision would modify the minimum hit chance of tohit rolls an entity makes against others.
Highly defense-centric power sets like Super Reflexes, and Bane/Widow VEATs would get enough +Bolstering buffs from their powers to take their minimum chance to be hit all the way back to 5%, hybrid sets like Invulnerability and Willpower would have less, maybe only enough to take it down to 10%, and resistance-based sets like Electric Armor and Dark Armor might not get any +Bolstering at all. Crucially, +Bolstering would also be present in powers like Fortitude, Deflection Shield, and Ice Shield, and -Precision debuffs would be present in powers like Darkest Night and Flash Arrow, giving support characters back some of the relevance that they've lost with the proliferation of IOs.
I don't expect this to be a popular idea, since it would be a straight nerf to any character that softcapped their defenses and doesn't have a set that would grant +Bolstering, but I think it's in a good spot where it increases the difficulty of the game for player characters performing at the highest levels without harming player characters performing at more average levels.