I'm going to bump this, because I think it's an interesting thread.

A few ideas on my part.

Make your own bowler, including different styles, rev rates, and speed to choose from, along with what he would wear, and possibly different bowling bags.

Give a limit on how many balls you can carry (such as 4 or 6 or something), then make generic balls sort of similiar to what's out today.  Or you could not place a limit on how many balls, but you could make it so they would have to be purchased, through gaining money from tournaments you win and such.

Online play would be a nice touch.

If you pull this off nicely, I'd be willing to slap down a good load of money for it.  The more technical the better with a big instruction booklet.  The only people who would buy a bowling game really would be those who should already understand the technical parts of the game.

Keep us updated, and good luck.