So I took some time to think over the opposing view to this-at least what has been said.
What I've taken from it is that people feel you shouldn't be able to stack DR and soaking items-that it becomes too powerful.
The thing about this cloak is that it only mimicks the effects of a spell that is used very widely. Of course, it acts as a permanent effect of that spell, however it also soaks much less total dmg than that spell. It also does not work in addition to that spell.
If stacking DR and soak is the issue at hand, I don't think this cloak is the actual problem that the people opposed to it are saying it is. It seem to me that the problem would in fact be the belts that stack with both the cloak or the spell, and that can -never- be bypassed. But that's only assuming it's a problem to begin with-which I don't believe it is.
The cloak is a weak imitation of a widely used spell, it doesn't work with it, it doesn't work as well as it, and as has been pointed out 5 dmg is fairly negligible to the people that put them to use. It's just enough to be worth using without being too strong as far as I see it.
To point to other items as your point and then point to this one and say that it's the issue doesn't, to me, make sense. If your problem is with those items then talk about and modify those items.
A vestment of faith combined with stoneskin doesn't add the two together, you get the more powerful spell version until that wears off. But stoneskin does stack with these belts that you're bringing up, just like the cloak does. Nothing ever pierces these belts DR, and even a +5 soak 5 vestment of faith can still be pierced. I'm not saying it -should- be +5 soak 5, because this cloak was always a cheap imitation of stoneskin, though persistant, which made the fact that it soaked far less than stoneskin irrelevant and the item still worth using.
In the spirit of a rebalance, it should be changed, but a rebalance is making it +4 soak 5, because that's what the current form of stoneskin provides, that's what can be pierced by greater magic varnishes and a lvl 16 greater magic weapon. You can stack it with belts, sure, but stoneskin does that already and does it better, as does greater stoneskin which can now be cast on -anyone- not just the caster.
You might, I imagine, think that the belts might not be able to have their DR be bypassed-but they only apply to a certain physical dmg type. And that's true, and it's also true when you stack them with stoneskin or a vestment of faith. You can't have it both ways, and so as far as I see it, the belts are either the problem, or there is no problem.
So, if I'm being honest with myself, I truly don't understand what the rationale behind this was, and I would in addition to everyone else who has said so strongly urge you to change it to +4 soak 5.
What Philos is suggesting is that this item is not meant to be nearly as rare as people think it is. Its hard value is actually quite low; it's in fairly common loot tables. People have assigned a value to it based on its stats which isn't justified by any of the design philosophy behind it. We've adjusted its statistics to match its intended availability and value, that's all.
I still feel pretty strongly that you shouldn't change people's gear they already have. It was one thing with that massive change to enchanted items. Apparently, as was said, things were not how they were supposed to be. That's not the case here though. You found an item that has been well known for a long time, and you decided you didn't like how it worked. But instead of removing it and making a new one that worked how you wanted it to, you changed the current one. And I really don't think that's good form, personally.