In Mario Kart 64 I'd agree with the anti-blue-shell sentiment, but now they've actually made the item chances part of the character differences by giving karts an Items statistic. Note that all the karts with a high value in Items have lower stats, on the average, in other areas. So playing a high-item kart means you're driving a bit less fast, but you get better changes of really good stuff. Since I tend to play fun over win chances when I can, it means I almost always pick a kart with a maxxed-out item statistic.
So, I'd have to say that Loss Via Blue Shell is a bit more legitimate now. It still sucks that the only defenses are not being in first place at launch, star or ghost, though being way in the lead is another possible, though difficult, solution.