I don't disagree with most of the criticisms about the band--a better band should have gotten the break, they're still a bit sloppy live (but they've improved immensely--I've seen 'em four times, and each has been better, plus their stage presence is above anyone else I've ever seen), they massively abuse whammy effects and such, the songs are formulaic, the lyrics nonsensical, the music immensely overproduced, etcetera, etcetera. I immensely love them in spite of (and partially BECAUSE of) all that--it's power metal reducto ad absurdum. It's epic, triumphant, and as you said, catchy as hell.
And yes, they even admit in that video that it takes them a bajillion takes to get the solos. right. But they
don't speed it up. It just tweaks me when people say that--they don't.
"Skeptical Guitar World editors" attested to it. They produce it to a mirror sheen to eliminate all the irregularities (except on the original Valley of the Damned, which is a good measure of their actual quality as players), but they really do play that fast. Hence why their live stuff doesn't sound as good, but is still played at that speed. It will be interesting to see how their live album comes out, if they ever get around to releasing it.
As for adding faux fingerings in their videos... can't really say I care?
Again, wait for the live album. No way to add faux fingerings there. (I imagine there'll be a lot of post-production, obviously, but what can you do?)
Also, that's just the guitarists. The keyboardist and drummer are also both legitimate speed-freaks. Maybe not exactly Pontroy-esque drum complexity, but legitimate metal speed. The band has just been poisoned by people leaping to declare Herman and Sam the greatest guitarists ever, when they're just a couple of goofs with insanely fast fingers. It takes more than speed to make a truly great guitarist, but for what DF is trying to do, speed--and stage energy, which ALL metal bands should take an example from DF on--suffice.
P.S.: Incidentally, who's seen
this really well-researched About.com list of 10 "essential power metal albums"? It's spot-on, and includes both DF and Theocracy.