Honestly, haven't seen a post, but giving them the ability to have 100% sheild chance for 12-15 seconds would make them pretty epic.
I can see a lot of problems with this, especially considering what can be done with Energy Blast. Reactive shield is already pretty amazing, but a long term guaranteed shield like that would be absolutely *nuts*.
Something else to consider is that Vanguards are the absolute weakest tanks against I/E damage: VGs only pack 19% I/E DR and 2% resist chance with only Reactive Shield applying to the damage. Guardians pack 24% I/E DR and 5% resist chance with *all* of their CDs working against I/E damage, and Shadows pack 23% I/E DR and 2% resist chance with 2 CDs that are effective against it. The difference isn't *massive*, but, considering that the only mitigation mechanisms that work against F/T I/E damage are DR and CDs, it's a reasonably big difference.
Honestly, I'd be perfectly happen with a talent linked to Riot Gas that provides the VG tank with 50% F/T damage reduction (which is multiplicative, not additive) for 5 seconds following Riot Gas's use. It's essentially a worse version of Resilience tied to an existing CD which is already used actively by VGs. It wouldn't really complicate things but would provide the burst F/T mitigation utility that the other tanks get.