The HMV design, IMO, was great. Simple, effective and a nice glossy finish. The issue (like most initial release MCU since in the UK) was the lack of title on the spine.
The recent Zavvi edition has the advantage of a titled spine, albeit the UK title, and a group shot on the front, but suffers from a poor finish and a rubbish lenticular (which can just be thrown away at least). It is however the 3D version which the HMV version wasn't.
The Nova version has the advantage of having the US title on the spine, and I assume a glossy finish, but the front is way too cramped. The various slip sleeves are nice but no concern to me as I open everything. It's also the 3D version.
My ideal would be the HMV front and back with the nova spine. My ideal for AoU would be the 'A' logo on the front, the title on the spine and maybe a picture of Ultron on the back in a nice gloss finish. My guess is it'll be similar only with pictures on the spine.