Are the algorithms for PvP match making different between Ranked and Practice? I've been doing Practice PvP and have had a lot of ridiculous matches. I am level 109 Private and have been ranked with level 110 Warlords, level 50 Privates, level 1 Privates, level 70 Warlords. Most shocking matches to me are the level 1 and level 110. No way that level 1 should have been matched with me.
Practice will match anyone with anyone as long as they don't set level restrictions on the match. The way you should use practice is to get a friend of equal skill and level to play against to test out new decks before you use them in ranked.