Hi,
If you play
Persistent Petitioners I would recommend playing more that 8 as they become much better the more you have.
If i compare
Homarid Explorer with it, petitioners seems to be much better (also 3 in defense, ok for blocking, costs 2 mana less, has the potential of milling alot more). Also
Curse of the Bloody Tome seems pretty slow, it costs 3 mana and does not defend you. e.g. compare what other decks play for 3 mana and how much that affects the game compared to
Curse of the Bloody Tome.
also
Tome Scour seems a bit slow, and not very flexible. e.g. if the opponent plays delver od secrets turn 1 and attacks you every turn from turn 2 with a 3/2 you might be in trouble