Only 6? LOL. The fact that Cain was the first pick for NY in the first round, that she flamed out in the league, means it was a draft completely wasted by the Liberty. I don't have enough data to compile a historical draft perspective, but it has to be one of the worst picks in history. Even the most ardent Tennessee fan can agree with that.
As for "only 6" players taken after Cain still in the league, is that surprising? with only 12 teams, there is generally only a single draftee that is useful to a given team in each draft (unless a team has multiple 1st round picks). The fact is probably only the top 10 players in each class are going to really make it in the WNBA.
You said she was the worst top-5 pick in history, which is false because she wasn't a top-5 pick. Now you're saying she's one of the worst picks in history, period.
The very next pick last year was Novosel to Washington. Like Cain, she lasted one year in the league and barely made an impact. Actually Washington had two 1st round picks last year. Their second one, Lashonda Barrett, didn't even make it out of training camp. This was a Mystics team that went 5-29 last year and was starving for talent. They had four draft picks and none of them lasted in DC. I'd say their draft was just as bad if not worse, than New York's.
The year before that Ta'Shia Phillips was taken with the 8th pick. She didn't last a year.
The year before that Jacinta Monroe was taken with the 6th pick. She played 17 games in 2010 and 4 in 2011.
Shona Thorburn was also taken with the 7th pick in 2006. She avareged .8 points and 6.6 minutes for the Lynx in her one season in Minnesota. This wasn't the loaded Lynx team of today either. They set a franchise record for losses that season.
I guess to an extent, I'm proving your point of many draft classes being shallow. But Cain is hardly alone in being a "bust" for a top-10/first round pick.
I think the only way you could really justify it being a terrible pick would be if they passed on someone significantly better. As I said only 6 of the 29 players taken after her have stuck. Of those 6, only 2 are making major contributions, Hayes and Bay Bay Williams. They were taken 14th and 17th, respectively, so nearly every other team passed on them as well.
Was the pick surprising? Yes. She had absolutely zero hype leading into the draft. Looking back, however, it appears Whisenant took a gamble on a 6'6 post that can play when healthy in an extremely shallow draft. You can argue that Hayes and Williams could have gone higher, but I don't understand what singling out Cain has to do with that.
