Personally I think that only very minor tweaks are needed - if any! Going through the thread to-date:-
1) EoV work well in their particular niches - over the weekend for instance even I managed to obliterate a Warlord with 2x Cobras (their prime target of choice) - and that was with my usual crap dice
2) Fire-Prisms need to be used cautiously, but will likewise "eat" IG SHT (they just need to operate from behind cover in the rear of the battlefield - you guys do of course have lots of cover don't you??). I am less sure they need to be part of the "Swords of Vaul" and do not think they should have any stats changes at all - shortening their range for example brings them permanently into range of things that can hit them, which breaks them and we then get complaints about how underpowered, brittle they are etc - they are supposed to be brittle!)
3) Also, I do not think we really need to allow 6x falcon formations (much as I would like to have them).Essentially you need to positions things properly so that you minimise the risk to them (unlike I did over the weekend, where they were too close to some Warhounds that prompty doubled and obliterated them

)
4) Aspects likewise have their roles, and that is the whole point. the only real change I would make here is for all CC specialists to have 4+ armour, while all FF specialists would have 5+ armour. This would make WS 5+, HB4+ and also the stats would be slightly easier to remember

As for the 2+ HB change, I remain unconvinced that it actually does the right thing - I think fixing their armour would be more appropriate
5) I have some sympathy with Neal's suggestion on simplifying Exarchs and Autarchs which makes the game easier to remember. The only real criticism is that as far as I understand from a fluff perspective the Eldar characters usually come with a wacking great sword. But here I would definitely vote for simplicity over fluff.
6) I am less sure about the use of Aspect 'blocks'. I believe fixing the Exarch stats will actually resolve some of the issues Neal mentions. However forcing the use of blocks adds an unnecessary restriction and complication - and I am likewise opposed to different pricing structures because by and large they all work equally well at their particular speciality (with the possible exception of WS and HB). So I agree with Hena that we should leave the prices alone.
7) As for the other 1.8 changes, things like the Shields of Vaul actually seemed to cause more problems than they solved, so consequently I would be inclined to drop them