Speed is always nice to have, but unless you are really fast that alone is less of an asset as you get older. You don't see a lot of delay steals ,etc as you get older. The Catchers are just too good unless you are a blazer. I also think that as you get older if you are really slow it's a huge detriment unless you can just hammer the ball. Grounding into DP's, thrown out from RF,etc. On your team how do the deploy a defense if they only have 4 fast players. You can be average speed in the OF, but if you can't run at all you will get killed?