Anyways, onto your suggestion. I like the feel of it, and I like the idea of it, but I think it needs a few modifications for these strategies:
1. Damage potions. Lots of them.
2. Constant knockback.
3. Knocking it into a hole in which it cannot escape.
4. Digging straight to the treasure. (If it cannot get there itself, how can it defend the treasure if you can just dig to it?)
5. Hiding behind a pillar and hitting it while circling around.
I have suggestions for each of these.
1. Immunity or reduction to potion damage.
2. Make its reach longer than our reach. This makes knockback less effective as well as making it harder to fight.
3. Climbing. Combine this with number 5 so that an overhang won't stop it.
4. There is a switch on the ceiling of the temple that the gold golem pulls if you open a chest within its range. This switch detonates the TNT.
5. It can crack through something if it hits it over and over again.
Those few modifications aren't small at all. You found strategies to fight the boss, it's not supposed to be direct head to head combat without workarounds. You've clearly not been here long enough to realize that this suggestion has been fine tuned for a long time to be easily implemented and fit the Minecraft theme. Your adjustments would make it overpowered, be a pain to code, something that doesn't fit well into Minecraft as a simple guardian, and just seems like your trying to make it an actual direct fight (which would be useless, not to mention not worthy of the loot). You clearly did not read the whole post considering a lot of your "issues" have been addressed.
Also, I doubt anyone cares that you find something annoying, as many people have not, and it's actually quiet standard to have things like that in suggestions. It making you want to reject it right away is fine, because do notice you can't reject it since you have no authority in Mojang nor does your lack of support affect this topic whatsoever. If you had the read whole topic, you would have noticed people who actually do have some say, respect, or what-have-you have actually supported the idea. So please, stop with your authoritative attitude, since you have no authority.