I like solitaire; I've always found it strangely soothing. It's also
what I do when I'm on hold, or on a boring phone call. I've got
Windows XP and I've noticed a few differences. One is that the
reshuffle speed at the end of a game is slow; it used to be a function
of computer speed or power, because it got faster with each new
computer over the years. Two other differences I've noticed: a right
click will send up anything that can go up to the aces. secondly,
moving the cursor around, like left-right or in little circles within
the playing area will speed up the reshuffle at the end of a game.
My question is whether there are any other differences between the XP
and former versions of Solitaire.

I can't speak to Solitaire, but they really screwed up the XP version
of Freecell.  It used to be so nice, and now it's new and unimproved.

Little has changed over the years. Solitaire is solitaire. New decks
came out, the help file may have been updated and tweaked, and the
options menu may have been modified a bit. Look at minesweeper - I
doubt it's been changed at all.