Minority opinion, but I like the ostentatious displays. God is supposed to be the king of the universe, and any earthly leader doing the same things nobody would question. Why is Queen Elizabeth worth all the pomp and circumstance, the jewels, the cars, and so on, but God isn't. Why is it that you wouldn't dream of going to an audience with HRH in ripped jeans and a ratty t-shirt, but that's good enough for the God of the universe?
My two cents is that I find the reverse to be just as ostentatious in the opposite direction. People tripping over themselves to remove anything that's not absolutely mundane. Like you decided that organs are too formal, so you use a guitar. And decorations are too formal. Its still showing off, you're showing off by not being formal.