How is this bad?
As now for example, if I was a Samsung person the S5 is 6months old, so if I was upgrading now I wouldn't look at it. I'd look at the Note 4 instead.
Having phones at different times of the year is awesome. So regardless of when you upgrade you always have something new and better.
The thing is, the Note 4 is not a S5 successor, the two are differentiated; one is a compact and waterproof smartphone made for the masses, the other is a Phablet with a more sophisticated design, made for a smaller market.
The Notes get better hardware for two reasons, they are Samsung's premium products and they come later in the year. If the Note 4 came same time as S5 it would also have a S801 chip. There is on S flagship and Note flagship a year.
On the other hand with Xperia Zs, they have 2 flagships a year, an early year flagship then a direct successor later that year e.g. Z - Z1 (2013), Z2 - Z3 (2014). If Sony just did a smartphone and phablet it would be better.
In fact, you know what would be great? Sony do a Compact at CES, then a Z flagship at MWC, then a Z Ultra at IFA, or both a Z Compact and Z at MWC then Z Ultra at IFA, that would help consumers keep up with their products and people wouldn't worry about a successor 6months later.
HTC have done a great job of upgrading once a year and keeping their portfolio small, they are now out the red and in the black financially.