From a WvW perspective:
The concept is very fun and the golem is neat, however it does feel like a downgrade compared to the other two specs, more flavor kit than a competitive kit.
Allot of people covered the balance side of things so I don't have much to chip in that hasn't already been said, however there are two glaring problems that amazed me that you guys didn't think of and that I feel need to be addressed before anything else, as they destroy the experience out the get-go:
1) The golem does not have the "Attack my Target" F1 option to actually be able to direct your golem to specific enemies. If you guys are already going for a Engineer is now Ranger then please actually let us control the golem same way one would a Ranger pet. As it stands now, the thing does stuff on its own, and the only way to actually direct its anger at someone is by using one of the F1-F3 skills, which are going to be on cooldown most often, outside of that you just look at your golem attacking enemy pets or random people he fancies.
2) While the spec has the "Return to Me" F3 command that a Ranger has, it also is not tied to a hotkey, nor does there seem to be an option to tie it to a hotkey. Have in mind allot of us play this game with the camera option that lets you move the camera with your mouse, so our mouse is always locked and we have to use keyboard buttons to do things rather than press icons with our mouse. As it is now, each time I want the kitten golem to return to me I have to swap between camera modes mid combat and then swap back again just so I can release my mouse to press the "Return to Me" function.
Outside of that just a small comment relating to the comment when this spec was showcased on stream, stating that the defiance bar might be removed in PvP/WvW. If you do that then you might as well expect noone to play this spec in WvW, the animations for all of these golem skills are so long that it wont be able to fire off any of them if it gets interruted/stunned/knocked constantly.
In closing I'd also like to ask that you allow the character to actually move while you summon it, the fact that you have to stand still locked into place while the golem summon animation is going on is pointlessly frustrating, especially when even the Elite skill that summons it lets you walk around while casting it. And also please look into the fact that the golem is constantly getting summoned/unsummoned when you use your mount or glider. I don't mind it going poof when I do, but it should be like the Necros Flesh Golem, the moment you leave the mount/glider is just instantly appears next to you (if it is active), rather than having to wait for the "golem drop" animation 3 times over as I'm gliding/mounting about.