This reminds me of a story I read somewhere in early eighties, when a rock drummer was asked what he thinks about that new thing called rhythm-machine, which was about to make his job obsolete. He answered that he actually really liked the thing, as it will replace the bad and mediocre drummers, leaving the top ones with enough work to do. This has since proven true, and I think that an analogy can be drawn in the case of Bootstrap.
What I would like to see are more ready-made templates, such as thise at ThemeForest, that are based on Bootstrap classes and styles, so I could make the prototype in Bootstrap and just place their styles to change the look.