Epic 30k

[gregmita]

This is a big problem with the release. A lot of people who would be interested already have armies in a completely different scale, incompatible with the new miniatures. It remains to be seen if the set will get enough new players to make up for that.

[eptingmike]

I have been slowly 3d printing items to play Horus Heresy but in 6/8mm scale.  Looking at this release has me mildlyinterested.  However as the items I have been printing are scaled more to how I think they look best as opposed to how they should be scaled to reflect 'reality' I will likely pass. 
Regarding the interest of folks already kitted out with armies I don't think GW is marketing this or expecting to make sales to this crowd.  I think this is more for those who are playing Adeptus Titanicus already(maybe Aeronautica Imperialis to a lesser extent)as well as those who are subject to the allure of FOMO(no judgement as I am somewhat afflicted with this myself  )

[Cordvane]

I don't see the size difference as a big hindrance to use old miniatures. In the end it doesn't matter how big the miniature is or how many there are on a base, as long as they are on the right sized base and the army is size - consistent in itself. And for my personal feeling smaller Minis would look better besides the bigger new tanks and titans.