The best answers to reanimator are actually Karakas and Glacial Chasm which deal with almost anything they can come up with. Maybe Terastodon will get there through Glacial Chasm but the chances of that happening are actually way too little to justify putting 4 Leylines in the board. And no: we don't need anything but a single Crypt/Bojuka Bog from the sb against Dredge (which is an awesome matchup already).