This would ideally happen alongside making armors meant to tank effective and viable as well but it'd be wonderful if the warden shields in PvP were actually allowed to be used in PvE so that you can actually protect your teammates. Right now there really isn't any kind of dynamic to explore that isn't "rush and do lots of damage using meta items", tanking and protecting teammates via a strong shield would be fun.
It doesn't even have to be as strong as it is in Lockdown -- ideally it wouldn't be. Make it smaller, have drawbacks, something to trade off for being able to use it in other parts of the game -- but I do think it'd be nice to have access to the Spiral Warden's shields.
I'd be all for something like that. Always thought it stinks that there's no real tank class in PvE. All of the "heavy" armor sets and shields provide only marginal health benefits along with some pretty significant downsides. Something like the Plate Shield lines would be perfect for an extended shield effect.