I love your post <3 ^^
A PV is bad for me if it bores me and doesn't make me want to watch it again. Per definition, a PV is probably bad if it doesn't make the song look/feel/sound better.
As for me, yes it is the lack of images. I'm not nitpicky at all. I could care less about her strange outfit (though a gay friend of mine actually said that, I quote, "she looks beautiful", which I've never heard him say about anyone

-- I think it's the hair). But yes, seeing the same scene for an extended period of time is boring to me. Which is why I don't like the MW and GREEN PVs either, but I do like Days. =3
Well, the few exceptions weren't really pointed at personal favorites but at real exceptions. I mean, I like (don't) Leave me alone. I don't know why, I just do. However, I don't think it's a good PV from a subjective point of view as it's the same scene the entire PV. xD (Of course, if they were forced to do that due to budget then they did do a good job, but okey.)
The exceptions would be ballad PVs like HEAVEN, Daybreak, JEWEL, rainy day. I don't think I have to explain why such songs can have PVs with no scene changes. ^^
But for an upbeat PV like Rule, there should be more scenes in my opinion as the entire mood is different. Imagine watching the HEAVEN PV to Rule, haha.~
And I don't really mind it if I don't know what's going on. (Though in About You, the Ayu locked up in the ice cube was way more obvious than, say, MW.) ^^ But yea, MW had a set up like this:
- Scene with Ayu walking -
- Scene with Ayu in SM outfit -
- Scene with Ayu in red dress -
- Bridge with all different Ayu's -
- Scene with Ayu in a telephone cell -
& throw some random agents running around here and there.
I think that if you can actually accurately summarize a PV like that, it's bad. E.g. it would take way more lines than that to summarize About You, because it switches scenes so much.
[i talk too much]