The increase to lily generation rate as of patch 4.05 has undoubtable improved WHM in a variety of ways. However, several problems with the system still exist and should be addressed.

Problems:

1 The strategic uses of the lilies are still extremely limited
One cannot reconcile between usage for recast vs fight mechanics

2 Lilies do nothing on their own

3 Lilies generate too quickly in some instances
Getting stuck with three lilies and nothing to use them on

Solutions:

The most straightforward and simple solution to these problems is to add a passive buff to the lilies. The ideal passive buff would be a haste buff (perhaps 5% per lily) as in fits in thematically with the lilies recast reduction effect and benefits WHM's healing and DPS aspects.

On one final note I also think that the recast reduction being percentage based is unnecessary. It would make more sense to simply have lilies reduce recast by a fixed number of seconds (perhaps 10s 15s and 20s).