My AST is so weak, why?

[Sida]

I have healed some 50+ with both AST and WHM and as long as I stay in Diurnal their strength feels the same, especially after I learned to use Synastry. I have had some trouble with Nocturnal but that I think is more do my mindset not being used to the shield thinking.

However, as pointed, especially in leveling the tanks tankiness is vastly different and you need more takes than one on both to draw parallels on the class strengths.

Edit: took a look on your character and, unless you're having that weapon on hand just for show, you really should upgrade it if you're going to run 50+ places. While level 43 weapon can work to some extent in the original level 49 content, the streamline iLvl expected to content in HW is 115. It's quite a jump after level 50. If you were having that weapon on hand in your DV run it propably largely explains the troubles you had.