I would recommend once your team reaches 55th, seriously consider replacing the Paladin tank with a Death Knight.

The DK + 4x Ret, is a rather strong team for both PvE and PvP.
A Prot Pally is probably a better tank.
But the DK brings a lot of PvE buffs to the team, such as Horn of Winter (damage) and Icy Talons (haste).
And if you decide to PvP, Death Grip and the Ice Snare are both quite good.

Between four pallies, you're not losing much buff wise, from trading the 5th for a DK.
And it is probably the top melee composition for both PvE and PvP.
Worth taking a look into anyway.



A castrandom can get stuck, although it might not always.
If you only include instant abilities, as in no cooldown/refresh, then it cannot get stuck.
But if Judgements are every 10 seconds, Consecrate every 8 seconds etc.
It can get stuck on these, and will hang (nothing happen) until the spell comes off of cooldown.

The old behavior, was for a spell on cooldown to not fire off.
But the next push to call a different (well at least another) random choice.
And if you were to spam the key, you'd get different abilities firing off.

Unfortunately that is not the case.

For the Pally, if you are tanking, take a look at the 96969 rotation.
You won't have all of the tools for it, until you are 75th.
But it has the basic spells you'll want to use.