if you can deal with the limited bar space and no weapon swapping its not bad, not sure if i have seen many people use it in pvp though

empowered doesnt work at all in pvp (at least against players) so theres no more 1 shot heavy attack builds

You should have seen it before the nerf. [snip]

[edited for minor bashing]

As others have said, Oakensoul was much stronger on release. It included major damage and ultigen buffs instead of minor ones. These days it feels balanced to me. Even at it's previous power I found that, while it imbued the wearer with tremendous raw damage, they could have trouble finishing people off. Having only 5 slots and one ult between attack, healing and mobility limited your burst options. I got whipped hard by a Corrosive mag DK. I was on the defensive all the time - certainly couldn't defeat him - but his one-dimensional playstyle left him no options when his pressure didn't work. He had no true burst. Not that he wouldn't be very strong in AvA scenarios, but that was then. Nowadays I think you want to have a good reason to wear that ring. Maybe werewolf, accessibility issues, a simple training build or a preference for such builds.

It's perfect for lag situations in Cyrodiil where you can't bar swap to reapply your buffs.

Seriously though, it pairs well with Deadric Trickery since there are no overlappiing buffs between them.