They don't practice it enough obviously. Venus hit the fastest serve ever in the women's game, so obviously she has NO excuse not to have a blistering 2nd serve. I'm not sure I'd agree with it being the most important shot in the game, but it would definitely make them much better players. I thought they were both volleying alright today, but I didn't get to see a whole lot of the match. Elena was hitting great though.
Proudly donning the Nadal avatar until Fed either wins Roland Garros, or serves Nadal a bagel.