This is my Super Midrange paladin and it works really well.
There is 2 ways to play this deck either Try to get a bit more aggresive start or play with more defense. Either way you want to control the board all the time and use efficient removal. This deck can outlast Heavy Control decks but then you need to play conservative and save cards.
This deck has pretty much everything, Great early game, Good midgame and Some late game cards to finish it off. Oh yeah i run Ysera because she is a powerful creature that can control the late game and yes she works in paladin.
When i play i always try to mulligan for the typical cards like zombiechows, Knifejugglers, minibots, Musters but i sometimes also save shredders and truesilvers in my hand because they are just solid and super strong cards. You can also consider keeping a quartermaster if you have the coin and a Musterforbattle in hand.
Why not give this beast of a deck a try and you can always change it to the way you like it. Some people dont run Justicar Trueheart and they might replace it with another Murloc Knight or maybe a Loatheb. You can do whatever you want this deck and it will probably as good as its original form is.