You can't be both generic and have a signature sound at the same time.
All of their songs have the same composition, Sonata's stuff barely became proggy with Unia. They even repeat themselves at times. Since it's keyboard driven the guitars are either powerchords or scales. I remember joking around with a friend of mine that the drummer of Sonata only recorded one track and they used the sample in a number of their songs:
http://www.youtube.com/watch?v=LBeOtvpovYU
http://www.youtube.com/watch?v=5yszaOJHPjA
http://www.youtube.com/watch?v=WN2UQyXGReI
http://www.youtube.com/watch?v=ih1YTOob2PU
http://www.youtube.com/watch?v=ahjMrcHAVaw
But I understand what you're aiming at, maybe generic was the wrong term for it. Possibly formulaic and maybe predictable (without it sounding like I'm trying to insult them)-- I love all of these songs, and 95% of the stuff Sonata ever made but the sound they achieved before Unia isn't solely theirs.
Let's take your band for instance, you have a singer whose voice never reminded me of anyone, and the rough vibrato (I hope I'm phrasing it right) his voice, best heard at "...there was
a madman's cry for insufficient life." of A New Melody added a unique dimension to your music . It took me some 20-30 listens to match him to some other singers, and barely. And your songwriting in general never had me going "where have I heard this before", whereas when listening to Sonata, and after learning of Sonata and when listening to other bands I'd get these flashes "of it's that part of this power metal song". Yeah, maybe formulaic is the better term, I hate writing this as it makes Sonata sound like a lesser band, as those guys really left a mark on my life.
A crappy song that's catchy (which are plentyful) will always be better than a crappy song that isn't.
Despite understanding what you mean by that, I cannot accept coincidence as a means of enriching the song. I've heard far too many Limp Bizkits and rap songs that've caught my attention via their 'catchy factor' and I often cringe when I realise that there are masses out there who would consider it good music just based on the fact that they are somewhat earwormy. For one thing, anyone can spout a catchy beat; and anything that's got a familiar rhythm or is written in the few chords subconsciously known to everyone instantly becomes memorable.
Almost everyone knows the first 4 notes of Beethoven's 5th symphony
Beethoven's 5th more likely sticks to people because it's part of basic music education or due to its popularity in mainstream media. It's not particularly catchy if you ask me, but I know what you mean.
ps
Sonata's Unia and your debut both had something which is definitively not a sign of catchy music; they both took at least 10 listens over longer periods of time in order for me to absorb and understand them. They're far from catchy, but then again they're both great albums.
(had to edit the links because they were taking far too much space
)