True, MLT is not very fast. I've had it in my 2009 MKS, 2012 MKZ, and in my current 2015 MKZ. One of my main beefs is that using Voice Controls you are basically navigating the menus with voice, which can be very slow. It's often faster to just touch the screen to get where you need to be.
My own view is that overall, car manufacturers are terrible about developing user interfaces for the infotainment systems. Forget Sync entirely. What needs to happen is for Apple's CarPlay and whatever the Android system is to be implemented in the vehicles ASAP. Apple et al. have the best user interfaces, and if that can be mirrored on the car, the customer will be very happy. Customer is already familiar with the interface and knows how to use it. Car manufacturer costs will go down as they will not need complicated electronics to support the system. Win-Win for everybody.
I have to strongly agree with this. It seems like a constant complaint about most cars is the over complicated, over simplified, too many button, not enough buttons, why aren't there more features, who needs those features...kind of systems. What works for one is atrocious for another. With phones you get to pick what features you want and the complexity of the system, why not have that idea inside of your car? Your smart phone can already control most things in your house (if you really want it to) so you might as well push it into the entertainment system (with wireless charging...of course).