Stipulations have been added.

It does seem like a lot, but my perspective was:
  1. Eschew Materials is literally a feat that replaces a 5gp item. Many DMs ignore material components altogether. This feat is fluffier than Endurance.
  2. In Oriental Adventures Rokugan, Void Use is actually a buy-one, get-one-free feat. Every human is required to take an Ancestor feat, but can instead choose Void Use. If you take Void Use, you get an Ancestor feat with it for free.
  3. Invisible Spell is actually rather good.

Still and Silent are likewise generally non-stellar feats.