IIRC, Kai's conclusion was that it's the aging.
That has been my conclusion as well. The only German lager that I have ever done late hops in was the pilsner and schwarzbier. Even my bohemian pilsner gets hopped at FWH, 80, and 30. I haven't noticed too much of a difference in decocted beers and those that are temperature controlled through a Hochkurz schedule of 142/158/168 (apart from my level of exhaustion on brew day). For most styles though, single infusion works well. I reserve the Hochkurz for the bopils. All ingredients are important, naturally. Continental malt, hops, and yeast with low carbonate water (I'm lucky in that regard).
Pitch cold, and let it slow rise a few degrees to your fermentation temperature (48--50 F; 45 for bopils).
But with all of these things nailed down, these beers are always better if given time to age. The hop bitterness drops a little and every gets that nice blend of flavors that. For lack of a better description, early on, one flavor or another tends to be more pronounced; after a time, everything is more subtle and in balance. I have found that at around a month in the keg is where they really get good.
Not being able to get fresh German beer here is what drove my brewing habit early on. I have sought to perfect these styles for years. It is a long road, but as my beers have improved, it has been worth the effort.
The bopils I have on tap right now is probably the best I have brewed yet. I will miss it until I can get another one on.