I think flourishy doubles can have their place, but the thinking that should go into a standard double turnover should not be underestimated. It isn't an easy thing to handle a double as casually and naturally as you would a single card. This is something I spend hours on, turning over the top card in various different ways and then trying to turn a double in an indistinguishable manner. The tendency seems to be for most magicians to go for a strike or hit double all the time, which looks absolutely nothing like a natural turnover of the top card. Again, these techniques can have their place, but the overuse of them shows a lack of consideration for exactly what the audience is supposed to see.