This is my main pet peeve. I don't like how you have to send all your non google and corporate email through gmail to get it to work. I believe there would be alot more of us using Android if the mail client was somewhat close to what Blackberry has set up. I know my husband would buy a Droid or Nexus in a minute if the mail was set up without having to go through gmail.
As it happens, it suits me fine since I've been using gmail for several years. But I agree completely that the gmail "pass thru" is a dealbreaker for some customers. Even worse, it's a dealbreaker for many corporate IT departments either because of security concerns or lack of competence in managing their email networks.
Google faces a dilemma in this regard since they're pushing their own enterprise level email, calendaring, document, and collaboration solutions in direct competition with Microsoft's products; a problem that RIM (BlackBerry) doesn't confront.
As it is, there are some jerry-built solutions (such as the one I posted) and some third party solutions (such as the one noted in a post above) that can resolve the problem for an individual user. (And frankly, if one isn't willing to pay $20 to solve the problem, I don't know what to tell you. On the other hand, a medium sized corporation with a thousand phones may view a $20,000 cost as unnecessary when Microsoft or RIM don't involve such costs.)
All in all, as I've complained about ad nauseum on this forum, a major problem for the Droid (and other Android devices) is satisfying folks like your husband and a colleague of mine who returned his Droid because he simply couldn't put up with the complexity (and limitations) of using the phone for his business needs.
Until the Android platform "grows up" enough to compete for corporate clients, it's going to face inherent constraints in developing its market.