wanted to have it discussed by people who are better at theorycrafting than me. It's always better to ask then make a muppet of yourself
It's largely a non-issue since it's such a comparatively small amount. The only way that the 82 Endurance is every going to matter is if you're dropped down to less than 1k hp, which shouldn't be all that common as a Guardian. The additional Power is also going to do next to nothing (82 Power equals 19 Bonus Damage, which is going to equal to *maybe* 30-40 DPS). Even mitigation isn't going to contribute a massive amount since Blade Barrier has a terrible conversion rate. You'll manage *maybe* 5 less DTPS.
If you're honestly asking which is going to be more useful, in general, unless you drop down low very often, the Power is going to be *better*, not so much because of the additional mitigation but because of the additional damage. Really, it's just a matter of preference since it's such a comparatively minor contribution either way.