First of all, interesting deck. I just think its lacking interaction.
Disenchant and
Crush Contraband could help to stop Combos or remove important cards. Since your playing mono W
Renounce the Guilds could be a funny card ("we all have to sacrifice a multicolored card. oh, i can't, ive got none.").
Crackdown would also be a nasty option, since it only harms your opponents.
You got some
Lifelink, what about
Well of Lost Dreams to get some additional Card Draw?
Depending on your playgroup
Gideon's Intervention,
Nevermore or
Darksteel Mutation could be very interesting to shut down important cards.
Besides that, i would really think about the
Urborg +
Karma combo. yes, this would cause alot of lifedrain, but
karma alone isn't a big deal and
Urborg alone could assist your opponents in stead of harming them. If you want to Play the combo, i would suggest add some more Tutors like
Enlightened Tutor or
Idyllic Tutor.
About the number of angels.. 17 sounds a little less, but i would suggest go down to 28-25 for some more interaction.