Actually I sorta said the opposite for Gen 4; the issue is that most people find the proposed ranking list boring. You hit in the issue though- the most interesting duellist, Arceus/Darkrai/Shaymin/Manaphy, aren't really rankable due to promo status. The remainders tend strongly towards one-dimensional. Infernape is standard sweeping style, Torterra is your stereotypical tank, Palkia is a tanky slugger, Dialga is the same thing but can try for OHKOs, and Giratina has great affinities and mind-numbing durability but no offense to speak of. Empoleon having the buffing game option is the best that crew has to offer, hence why people are more interested in ranking other packages from other generations even ignoring draw.
Now that said, at the end of the day only a tiny fraction of the DL will actually refuse to rank a cast for being a bit one-dimensional, but they will tend to latch on to most other viable ideas ahead of it, as seen with Wild ARMs 5 finishing third in, what, 3 different ranking topics before making the cut? I think Pokémon, even Gen 4, has a bit higher potential than that, but the general trend is still there.
Aside: before someone asks, the Gen 4 promos are interesting for, in order; Arceus of can pick his damned typing and is the best pokemon ever, Darkrai is a top notch sleep whore, Shaymin has the Skymin option and has some fun tools to use Serene Grace with, and Manaphy, while not awesome, has a cool as heck utility tool in Heart Swap.
