Why? One of the biggest inspiration for D&D games is movies. The further the rules are from allowing me to do that cool thing that I saw in a movie the worse the game is for me. I'd much rather my game look like Indiana Jones than Civ 4.
I've seen this claim a few times and I really have to wonder how you did it.
You say 6 PC's, so for a 2:1 fight, that's 12 critters. Assume for a second a 10th level party. We'll go very challenging and create an EL 14 fight. That means you would have 12 CR 7 creatures. Note, this is an overpowering fight and I should be killing PC's here. CR 7 gives us Dire Tigers.
Ok, a pride of dire tigers decends on the party. They have an AC of 17 meaning the PC's pretty much never miss, but, 120 hp's each mean that they manage to stand up to 10th level fighter types for a round or two. Saves range from 13 to 11, meaning the wizard is going to have an absolute field day. However, at +20 attack, they aren't hitting the armored types at 10th level very often. A couple of AC buffs and the armor types are giggling all day long. And this is in an encounter that, by CR, should be overwhelming. The party should be retreating from this. However, because the baddies are so much weaker, not only is the party not running, they're pretty much able to ignore the challenge presented.
You say that minions get a "slight" offense bump. That's simply not true. They are getting a HUGE offense bump. And, remember, it's not a 2:1 ratio, it's a FOUR :1 ratio. That's four actions, as opposed to two. And actions that have a reasonable chance of hurting the PC's, rather than wasting time at the table.
See, I've run those large combats as well. And my experience has been the exact opposite of yours. So, I'm wondering what you're doing that I'm not. How are your groups acting as a challenge to the party?