I guess it's just discouraging to see one that's such an all-out assault on one's senses (or at least attempts to be) that just falls flat and doesn't excite or inspire
Let me make a film analogy: You have films like The Social Network, multiple Oscar/Globe nods, everybody and their mother went to see it, made a killing at the box office, real moving story etc. It had a ton of effects, you wouldn't know because most of them are subtle, and go to achieving the mood and the period. It's got all sorts of clever editing and digital wizardry in the background to make you feel emotions subtly. Very few will notice 99% of this stuff, because none of it is obvious.
Then you have film like Transformers. An amazing film with amazing effect, and a unique Spielberg-ian charm. The right balance of effects, action, and editing, to really entice you. The CGI is generally stunning, and does its best to make you care about characters that aren't really there at all.
Then you have films like Transformers: Revenge of the Fallen. Now, I loved the first Transformers, but was hugely disappointed with the second one. Ultimately, it was a disco, a sensory assault amounting to very little. Whereas the first had a simple plot, this one had a tissue-thin plot with more holes than a swiss cheese factory. The visual effects are clearly unmatched: ILM outdid themselves and should be proud of the work they created. Now, both Transformers films used CGI only when necessary, preferring to use practical effects (mainly because Bay prefers to blow shit up IRL instead of CGI-ing it), however, TF:ROTF had so much overload of everything that despite everyone going to see it and it making billions of dollars, none of it really amounted to anything. The plot was throwaway, the characters were so many you had no connection to any of them, and what's worse, you had people assuming scenes that were filmed practically were CG. It was a boring film with one or two really cool scenes and amazing effects. Even most of the action sequences fell short of the first one.
And then you have films like The Kings speech, which have barely any effects at all, and yet still are universally acclaimed for its drama and acting.
AMV's are
kindaexactly like that. Effects are neither a pro nor a con, it all depends on how they're used. I made an effects-heavy video a year back, it's Avatar:The Last Airbender so it's not on the Org anymore, but it did make it to a few cons. Those that praised it praised the underlying concepts, those that bashed it bashed my (over?) use of effects. I like the effects I used, I think they worked great with the story I was trying to tell, but if I made an alternate version with all except the most necessary chroma key/transition stuff, the essence would still remain.
The video you posted is actually a lot less impressive than it seems like, and it looks like the guy just dragged-and-dropped every transition/mask layer that was available with Premiere/Vegas/whatever he was using. He had some decent sync, and just dropped an effect whenever there was a beat. Nothing special here. Someone could probably teach you how do it too in an hour or so just by standing over your shoulder and pointing out step by step what he did. In my effects vid, every single effect was chosen for a reason, a purpose to enhance the story I was telling. The one you posted was just a hodgepodge. If you learn the storytelling first, with the effects second, you will be far better off in the long run. So don't be disheartened! Learn effects as a complement, not a substitute! Pick up tricks as you go along editing for story/comedy/drama, and those times you go "hmm, I feel like something really flashy here would enhance the video as a whole." I think you might just find that works for you.
Happy editing!