The temple chests could just be locked until you use the key to get in. That way, you can keep all the hoik (and similar) shenanigans, plus put better loot in the chests. You can still get the solar tablets by crafting, so I'm not opposed to this change.
On the original topic of the Temple Defender, I don't think it's too nessecary. Correct me if I'm wrong but the enemies always spawn, so they'll slaughter you in prehardmode.
The only thing I could see a defender useful for is to oppose disarming the place (cutting the wires and placing peace candles). Then again, unless you are doing something to cheese them, the enemies still spawn.
...a golem head pet would be cute though...