Just proposing a Feat with a similar usage as the 3.5 Feat that did this.
It basically allowed you to make two attacks as a Standard Action (i.e. after Moving/ Charging/ etc),
although they both used the same Attack Roll (which doesn't give you a greater chance "at least one" will hit).
It should have a BAB requirement. I could see a similar ability, maybe stacking, maybe not, working off of 2WF.
This obviously helps melee-types who are otherwise limited to one attack per round, unless they can Full Attack.
Given that similar Feats already exist for Ranged Combat (Multi-shot, Shot on the Run), I don't think it's too far out there to implement something like this for Melee-ists. Since it is BELOW their # of attacks available with a Full Attack, it isn't completely negating the distiction, like a Pounce ability would.
Efficient Strike (Combat)
You take quick advantage of any opening to deliver a number of blows.
Prerequisites: BAB +6
Benefit: You can take your second iterative attack as part of a standard action, or as part of a single attack of opportunity.
Normal: You may make only one attack as a standard action. Each attack of opportunity an opponent provokes allows you only one attack.
And then of course you'd have Improved Efficient Strike (BAB +11), Greater Efficient Strike (+16), and Epic Efficient Strike (aka "pounce")(all attacks).