I think VW do concentrate quite a bit on their enthusiast followers actually.
They are very aware that there has been a strong following of their products since the aircooled days, they are very aware that there is a massive worldwide GTI scene following and that many owners have been there since the mk1 days.
VW bring out specials every year to display at Worthersee, and many of these models are testing the water as to how the enthusiasts take to styling etc.
VW are very aware that they have a lot of dedicated repeat buyers that not only bolster up the new car market but because of the cars' popularity it holds up the value of used cars and keeps the VW brands a cut above the other mainstream small car producers.
As quick examples, we had the W12 GTI which was technically a mk5 but had the styling features of the mk6 to prepare people for the looks of the current VW noses. Then there was the Worthersee GTI in 2009, forerunner of the ED35, colour and all. Similar seats, same darkened lights, the black optional 19s on the 35 etc etc.
So as Snoopy says, VW won't dilute their GTI brand. It took years to build into it's iconic status and has always been the best allrounder hot hatch.
To answer the hi-tech demands of the well heeled play station generation they have the R brand. Carte blanche there to try out wilder things than the GTI stands for but still very recognisable as an understated and discreet VW Golf.
So they're doing something right.
The ED35 may be a bit underwhelming, but at the end of the day it isn't a particularly important anniversary, it is just a convenient run out model to bolster sales until the mk7 arrives in a couple of years.