Some good Paladin news!

[Vitandus]

Will problems such as lack of MS debuffs, interrupts, distance closing, and susceptibility to mana burns/silences be addressed?

Mana burns - yes.
Distance closing and interrupts - we are considering giving Ret or paladins in general some new utility to make up for all the nerfs we have made to their damage. It will almost certanly not be MS though. You can find a thread where I recently attempted to explain why we don't want to give out more MS debuffs.
I haven't heard a lot of silence complaints from paladins recently (more than normal I mean). Is this a new problem? Care to elaborate?

Interesting commentary about Arenas driving the decisions for the nerf:

The problem was that the cooldown was irrelevant. The paladin could wing + bubble, then go in with a stun, DS, CS, JoC and maybe Consecrate, all within a few GCDs. If the poor sap on the receiving end was below 35% (now 20%), which was likely, he would get hammered as well. If somehow the target was still alive after all that, or had an ally, the paladin usually had enough mana to heal himself to full. Then, even if the battle was over, the paladin had enough mana to just go on to the next target (minus bubble). In Arenas this didn't matter of course, because with a death that early, the match is usually decided. This strategy was the entire PvP problem with Ret in a nutshell. It didn't take a lot of skill and was impossible to counter. Most other classes can't open with that many abilities at once (ignoring the bubble defense and healing potential). Players complain about rogues stun-locking them, but at least that takes some skill from the rogue to do things in the right order and usually requires an element of surprise.

Ghostcrawler thoughts on snares/CC:

The Mortal Strike debuff is a tricky one. We do realize how potent it is in Arenas and we have used it on occasion to give classes or specs a good role in Arenas. But then recently we stopped and asked ourself where we were going with MS. If Ret and Enhancement and Feral and whoever ends up with MS, what's the point really? Shouldn't we just start you in Arenas with healing at 50% and be done with it? This is a topic we're thinking a lot about.

On utility, the designers did agree that if we were going to keep hurting Ret's burst dps, which is a big thing they brought to a team, that we needed to give them some kind of tool to make up for it. We're not sure whether that will be a snare or interrupt or whatever, but the feedback on forums like this one will certainly help determine it. I am surprised to hear you say you don't have a lot of control, becaue I think that is the preception of a lot of classes on the receiving ends of your stuns.

Thoughts on Divine Storm not being Holy any more:

If Divine Storm went back to Holy, its damage would have to drop by a lot to compensate (maybe 40% or so). There are some design advantages to having it stay physical. For example, an Arena team can send a plate wearer to fight the Ret pally since Divine Storm will do less damage to that person.

Ultimately, we would like to have the spell feel more different from Whirlwind, but understand that our first priority was just to get paladin damage under control.

On our mana debuffs:

I really don't see a lot of paladins judging Wisdom in PvP. Unless you are being mana drained a ton (which as I mentioned is something we do plan on fixing) I don't understand how you can be going out of mana while fighting someone. Now if you blow a lot of mana, you may have to pause in between fights. Most mana-using classes have to do that.

[Vitandus]

Our eventual plan is to put Divine Shield on a shared 30 sec cooldown with Avenging Wrath. We also plan on changing Divine Shield's attack speed penalty (which isn't really much of a penalty) and have it apply to all damage done while the bubble is up.

Divine Protection would no longer have the attack penalty, but since Prot paladins typically talent out of that penalty, it won't have a big effect on tanking (though obviously that talent would need to do something slightly different).

All of this assumes that preventing AW from being used with DS actually makes the Ret tree a little more balanced. We'll need to monitor that a little bit longer first.

We are going to go ahead and change the mana drains to a percentage of mana so that Ret paladins don't lose so much larger a percentage of their mana than casters with 15K mana.