Then there's the whole two trigger pull weight thing. Which is the central issue. "That's not a problem, you can get good at it" is the typical response, almost always by some one defending a DA/SA purchase. The real question is, why should you have to? SA triggers are faster and crisper, DAO triggers are lighter than the DA pull and consistent, and striker fired pistols are also light and consistent. Bottom line, all have the benefit of one trigger pull.
Taking that a step farther if double action/ single action is so great, and is easy to train for, why not simplify things, and make it double action only, or single action only? Traditionally the path to success is found in finding the fastest, simplest ways to do things. Notice that in competition, revolver shooters don't thumb the hammer back after every shot, they simply shoot double action. Some are very, very fast and accurate. Just as much as anyone with a semi auto of any style. This leads me to further believe that DA/SA on a semi auto is superfluous at best.
In my opinion, any DA/SA pistol would be a better firearm if it picked one or the other, instead of some hermaphroditic concoction of both. Sure I, or almost anyone, can train up to the point it doesn't matter. But then... what's the point? If a DA/SA pistol can be shot just as well as a SAO, why spend any time and effort when you can just get a SAO? Nominally 1/15th of your trigger pulls are going to be DA anyways (or less). What advantage does the initial DA pull offer besides needing to train to overcome it to shoot the SA pulls that are the majority? Safety? The ability to carry hammer down? Really it seems like the largest benefit of DA/SA is for people that are scared to have the hammer back on a firearm, probably why they became so popular with police departments looking to PC it up.
In summary, DA/SA does neither DA/SA effectively, is made for people who are scared of cocked hammers, and incurs a training debt to have the same ability as people just starting on dedicated DAO/Striker or SA firearms.