Yes the LotR system is awesome. But that means changing the whole system of BFG, a bit out of scope I guess.
With MSM, the msm holofield combination protection works in a way, yes. And in a battle with sparse terrain it can even work against fleets with only short ranged weaponry and slow ships. But versus fleets with long-medium range weapons (Chaos, Tau), fast fleets (Marines, Necrons) and ordnance fleets (Tau, Nids, even Orks!), the Eldar go down and down faster.
As for DE movement: well, it isn't bad but DE are currently designed into a one-trick pony for dull battles. Playing longer battles makes it death DE for sure. In character perhaps but it could be done better I think.