Ok, to begin with, what constitutes the different tiers for Eldar? If we would have to split the eldar teching into three tiers, what would it be? Personally I guess Tier 1 would be before Soul Shrine, and Tier 2 before Mobilize for War and Tier 3 comes after that, does that sound about right?
Now, Tier 2 can come extremely fast for eldar, I build soul shrine almost straight away so I never even get into combat until Tier 2, which makes it seem like you cant really talk about three tiers with eldar, the other races have distinct Tiers where they have different tactics and the transition between tiers are tactics in themselves.
Next, I dont really see a reason to go into "tier 3", ie mobilize for war. Even in really long 1v1 matches theres really nothing that BLs and infantry cant handle. The upgrades after MfW arent really necesary and neither are the vehicles.
The only thing I even see as interesting is maybe some fire prisms for harrassing all over the map and well, avatar or something. But if played correctly I dont see why you would want to go into MfW even in fights with several players, I just simply dont see any big gains compared to not going into Tier 3.