This actually isn't a bad idea- an "Atma" of sorts. Have it give the player the "specials" without the regular stats. For example, RDM could have (and would only be in effect as) :
Legacy of the Warlock (turn in Warlock's +1 Armor Set):
Enhances Fast Cast
Legacy of the Duelist (turn in Duelist's +1 Armor Set, have Atma of the Warlock (which gets consumed in the process)):
Enhances Fast Cast
Refresh
Enhances "Spikes"
Legacy of the Estoqueur (turn in Estoqueur's +2 set, does NOT consume Atma of the Duelist but requires it):
Enhances Refresh Potency
Enfeebling magic casting time -12%
Increases potency of Enfeebling Magic 10%
Increases Enhancing Magic Duration
Enhances "Saboteur"
Enhances "Composure"
Set it up that if two Legacies give the same bonus, only the higher one applies.
Voila, we've just ripped a good sized chunk of inventory free from many a player and converted them into an Atma-like system instead.