I'll weigh in. Let's move away from raindrops and airfoils for a minute and talk about cars. Because I have a '68 Corvette which I've owned for many years, I'm most familiar with that. When the Vette evolved, the C2 (1963-1967) used to experience severe front end lift at about 152 mph, to the point where you couldn't steer it anymore. The C3 was designed with a much sharper front nose and longer, smoother body. It's beautiful to look at, but actually wasn't that aerodynamic either. The C3 Vette, (1968-1982) had almost the same CD as the 240Z in fact. But it did reduce lift significantly over the C2, for a higher top speed, approaching 170 mph, so it was an improvement. The Kamm tail of the early C3 was actually more aerodynamic than the smooth taper tail of the later C3. So they brought it back starting with the C4. The wedge shape of the C4 (1984-1994) was a big improvement. The C5 was the best, aerodynamically, but it's not nearly as attractive.
So my point is, the C5 and C6 have more of a rounded nose, not unlike a teardrop. But unlike a teardrop, the abrupt end to the tail was found to be far better. The Corvette was designed as an early attempt at aerodynamics, but on paper only. Through trial and error, they finally learned what to do. Just like Nissan has also learned what to do, and has improved their Z aerodynamics through the years. The new 350Z is far more rounded than the much more beautiful 240/260/280Z.
Thing is, what works at very high speeds is different than what works at lower subsonic speeds. That is why supersonic jets have sharp noses. The behavior of the slipstream becomes much more fluid as speed increases, and the rules change. Simple as that.
I really don't worry about the coefficient of drag on my '68 Corvette. It has a 427 race motor in it. I figure if I need more power to hit 170 than a later generation Vette, I just hit it with a much bigger mallet. What is much more important than maximizing your CD is maximizing your ground-sticking ability. The C3 Vette had almost a 20 mph higher top speed than the C2, because they may not have fully understood how to build a lower CD, but they very much did know what worked on the race track. You can always install a bigger hammer, guys. Then it doesn't matter how low your CD is.
Cheers.