Re: Samsung's Problem
"I think that Samsung's issue is ...."
I agree with your comment about small improvements, but I see the problem the other way round: With the S4 (at launch) and the S5 they created a real problem of pricing themselves out of the market. That appears to be driven by excessive ambition on margin rather than the bill of materials.
If they'd priced the incoming handsets at more credible price then it would have been an easier upgrade decision from the previous model (or less of stretch for those aspiring to upgrade from mid-market models). But like you, I'm happy with an S3. In a year or so's time I'll probably upgrade to what will then be a discounted end-of-line S5, unless the S5 replacement comes out at a much better launch price - which I can't see myself.
This premium pricing is just corporate vanity. Samsung need to decide if they want volume sales at lower margin, or are prepared to sacrifice volume to be able to report big margins on the new model. I think Samsung's big cheeses think there's some magic sauce, and if they can find it they'll be like Apple, able to do premium prices and some volume. Samsung are wrong - Apple have defined and filled their own niche, and own their own software - but I doubt they'll see that.
So here's expecting Samsung to repeat the pattern: an even bigger S6, with a titanium chassis, me-too sapphire screen, rhino-horn backplate, iris scanner, pointless higher res screen, higher pixel count on an otherwise average camera. And more Sammy bloatware pre-installed, all for £1,000 a pop.