Just did 2 test matches in the PBE.
One where I tried a Tiamat build with BorK, and one where I went for SotD with movement speed and anti-CC items.
Volimat with BorK:
Runic Bulwark, Randiun's Omen, Mercury Treads, Maw of Malmortius, Ravenous Hydra, Blade of the Ruined King
Farming is fast and easy with Tiamat now. The new particles and the cleave active makes it so satisfying to use. I like it far more than I did Ionic Sparker, sadly, for champs like Irelia, Shen and Voli, it doesn't work as well with our kits as Ionic did. I was actually doing some damage with Tiamat + BorK, BUT, I do not feel like BorK is a good investment because on SR it does bonus physical damage, and with all the armour around you just don't make good use of the on-hit bonus because you don't have the penetration. Switching it out for Bloodthirster is a no-brainer, and it should boost both sustain and damage. I'd also switch Maw for Atma's. Less damage, but you don't need all that MR in most fights. Armour will be more useful most of the time, and Atma's is cheaper too!
Should be viable on live when the patch comes, at least for normals. I am by no means the person to judge what is viable in ranked and what is not.
Crit Burr with anti-kiting spec:
Runic Bulwark, Randiun's Omen, Atma's Impaler, Mercury Treads, Sword of the Divine, Zephyr
Let me put it this way. I felt like I was playing Master Yi. Insane movement speed, and with SotD turned on, I got 2.5 AS. That's right, max. Q + Ghost got me to 638 movement speed. Imagine if Yi had a slow and a fling... and was utterly untouched by CC. That's right, CC was bouncing of me. I never even noticed slows effect me any any significant way, they became so short and reduced and I was also, very, very fast to start with. Oh, and this "Yi" was very beefy too!
The drawback is of course, you don't do anywhere near Yi's damage. But you have some insane burst, Using SotD wiill make you instantly do 3 crits. Max attack speed bro. Crazy. Followed up by Frenzy and especially if you had R up, will severely hurt a squishy if not outright slay it. This is in 1.5 seconds.
Changes I'd make? Well, switching out Zephyr and Boots of Swiftness for Mercury Treads would free up space for Infinity Edge, which would be an insane DPS increase. But you won't be as immune to kiting.
And for the record, I don't think I've ever played such a fun Volibear build before. And I have tried a truck load of builds with him.
I do not think this build will be viable like I do the Tiamat one, not yet anyway. I'll have to do more testing. Right now you either rush the tanky items (in their earlier forms) and lose out on damage and fall behind, or you play a VERY risky game of high-risk high-reward where you rush the DPS and speed items. In a real fight on live, I do not think you can pull it off.
Tried both builds some more with the changes I thought of. Both work very well. Tiamat let's you farm better and you can do a bit of consistent damage. This is very much aided by the Tiamat active, it let's you deal much more damage than you could before with an AD build on Volibear.
SotD works very well with IE on Voli, especially with an Atma's tossed in. You don't get the easy farming and sustain that the Tiamat build offers, but in raw damage in a 1 v 1 this wins brilliantly. Amazing burst, followed by pretty good sustained damage.
So far, I'd say Volibear has gotten quite a bit stronger and MUCH more flexible in S3. Also, Boots of Swiftness. Crazy stuff when combined with the defensive tree and a non-merc treads tenacity source. A Volibear without kiting problems is TERRIFYING. But he still needs some form of innate tankyness, and slows are going to be a lot weaker against a lot of people so this could be a problem. But the squishies you want to feast on will probably not venture that deep into the defensive tree or try BoS + Spirit of the Ancient Golem/Zephyr over Mercs.