About 10 years ago for a few minutes, Aluminum is a mid range material for frames now, Carbon is where it's at; nothing wrong with Steel though.

For your potential new bike, it's 6 years old, and if ridden hard during it's life, would expect the groupset / wheels to be worn out, at least with your current bike, you know what it's done.

You have made no mention of will the Lemond fit, which is a big issue for any bike. I you want to go faster, ride more, the bike can only help so much.