Thanks. I'll swap them for other minions then. I'm considering Mind Control Tech, Shade of Naxxramas, Earthen Ring Farseer, Razorfen Hunter or Injured Blademaster.
I think MCT is good if things go out of control but I don't really know if I like its randomness.
MC Tech is OK for it's stats if you have to just play it onto the board. Randomly taking an enemy unit, puts the card in the crazy powerful territory. It almost doesn't matter what it grabs, even taking a 1/1 makes it better than almost any other 3 mana play. The problem is that you won't always be able to take something, but right now it's a pretty good card to squeeze into any deck. So I would only run a single copy and be prepared to hold on to it for a few rounds.
Shade of Nax is great for any deck that has buff cards or benefits from having a body on the board. If you can hold it back for a turn or two before attacking with it even better.
Earthen Ring is a good card if you need efficient healing. It's used in Rogue a lot because they spend a lot of time hitting things with that tiny dagger and so any hp recovery means a lot.
Razorfen is a fairly weak card for the same reason the 1/4s are. It gives your opponent the chance to make favorable trades.
Injured Blademaster is a great card if you have access to healing. It's a good card stat wise, but can be great in healing combos. It's a staple in most priest decks.
For the deck you listed, I would suggest another Shielded Mini bot as their great targets for buff cards.
If you're looking for a 3 drop specifically try these
Raging Worgen - When damaged it gains windfury and bonus damage, so buffing him up turns him into a game winning minion.
Scarlet Crusader - The Divine shield usually allows her to live that extra round so you can get your buff on her or allow her to trade into an enemy.