A good majority of the bike I modernize respond very well to the newer components and wheels. It may take a little parts swapping to find a frame's particular preference (ok, frame + parts + rider's style), but it's happened. A frame's "true character" is revealed most clearly. Race-framed bikes seem to me to be pretty amenable to modernizing as they are all about speed and modern road groups keep getting better at that sort of singular focus.
More and more lately, I look to equip non-racing bikes as original or in the spirit of their original components. Not everything has to be a slave to speed and adrenaline and hyper-focus. Seattle still has steep hills and active traffic, so I must accommodate, but otherwise, it's not about the rat race and continual upgrading. I'm getting older I suppose...
