But does the MW have better overall offenses than the offense optional big ten?
Yes and no - at least the part of the Big 10 Iowa plays the majority of its opposition from.
Although there are some duds - Wyoming is essentially Minnesota. Colorado State was awful, Hawaii was bad, UNLV is OK, New Mexico is bad, San Diego State is good but better defensively so they're kinda like a Iowa - Illinois - Minnesota
So its not a explosive conference. I would say actually as I go through the list - its probably comparable. Boise State isn't what it used to be.
There's Fresno State - and then a lot of meh in terms of true scoring power. Air Force can score on you but that offense generally means its not scoring 40 (averaged 27 last year in a 10 win season)
Its still a fun, competitive conference. But with Boise State not being as good, Hawaii not being at peak effciency and missing the TCU / Utah's of the world, its not a wide open conference offensively anymore.