Ian,
There's enough artistry in creating a functional, enjoyable, compelling, sustainable golf course, expressed in the language of GCA, there's no obvious need to add on top a layer of symbolism.
That said, the examples you cite introduce a level of whimsy that seems perfectly at place in a course. The risk, as with the Mickey Mouse green, and the hand bunker, is that the symbolic feature draws attention to the fact that the course may otherwise not offer much else to distinguish it.
Back when Curley/Schmidt were running the design a hole contest I put quite a bit of thought into this question. The symbolic treatments I found most compelling were those that wove the symbol's larger meaning into the strategic intent of the hole. So, for instance, a "tiger" hole would reward, direct, powerful play. The "dragon" would reward indirect play, and punish the direct route.
You could argue some of the template holes do this. The redan challenges you to attack the fort. The Sahara to cross the desert. The link is a bit tenuous, but the idea is there. Bring the symbolism into the golf strategy, not just as an adornment.
Dave