If it's an intended change, it's not a good one.
PvP mechanics aside, it's basically an annoyance if you have a high enough haste. But the real problem here is that it's been debatable that stacking mastery at the moment has any benefit at all for ret paladins.
The problem comes down to diminishing returns for a proc-based mastery. As it was before 4.0.3, my testing showed a DPS loss from putting ANY mastery on my gear if I was sacrificing crit or haste for it. Focusing on mastery also made DPS very lumpy, rather than the smooth increase that haste and crit brought. (Crit, while being a probability stat, effects basically everything - so it evens out more quickly than mastery does.)
I love it when Hand of Light procs, but this change only makes the issue with HoL procs stacking on top of themselves worse.
If the intent is to make the effect non-spammable, then that doesn't even work because if it procs back to back and you have even one charge of Holy Power, then you can still spam TV.
So if their goal is to make us never stack mastery, then this is a good change. If they want mastery to matter to ret paladins, then this is a bad change.