Yeah, Lucas works in metaphors. I like Mustafar, but sometimes less is more. My idea of the temple is not the same that was used in the Star Wars films, which were more animated than real. I admit, I would like to have seen the end battle take place at the temple, but one that was a real life set piece. Take for example this comparison.
While I think Mustafar looks awesome, I would totally prefer the dark atmospheric look that was presented in ESB. I thought if they had built a set piece like this, rigged it with smoke, fire, dark, eeriness, it would have done more justice than the colorful Mustafar, as beautiful as Mustafar looked, and as goreous as it was, certain parts like Anakin riding the droid and them battling on the platform looked horribly unfinished. Again, that's not say I hated it, because bottom line is, I still liked it. But I would have totally preferred the eerie look during the end duel, especially at a place which signifies what Anakin and the Emperor are trying to destroy, and what Yoda and Obi-Wan are trying to save in metaphorical terms.