Completely agree. I had to use an S5 yesterday and I was totally lost trying to do the easiest of things. The problem is Samsung got into the market early and strongly and as a result built up an enormous user-base (I guess particularly with the GS2), so as long as no other Android-based phone manufacturer puts such effort into promoting their phones and actively show the benefits they bring then they are going to struggle against Samsung. Product placement isn't enough.
You have to think Samsung's user-base will gradually slip away, diluted by other manufacturers, especially as the Chinese market takes hold, but us techheads aren't going to be the ones driving it.
And let's face it, even the new Moto and Z ranges have serious flaws too. Neither offer wireless charging, the Moto is missing a fingerprint reader and the camera seems it still isn't up there and the Zs have those humongous bezels heading both north and south and the lowlight performance doesn't appear as strong as the Samsung's. The Nexus 2015 range both look butt-ugly and will have weak cameras, but otherwise look ideal.
We say it year after year, but why is it so hard to make an excellent all-rounder?