One way casinos (actually, slot makers) make their slots more popular is by making exciting bonus games.
Currently, the style is to select one of several markers and you are instantly shown your prize, or lack thereof.
It would take some work to animate it, but popular slot games display animations, involve multiple selections, and each selection will win "something" it's just that most will only win a small prize. This can be tuned by a luck modifier to whatever you want it to be.
A great example starts at about the 1-minute mark of this video:
http://www.youtube.com/watch?v=vqrKdrg1GnA
In it, you will see that the player can pick 2-4 out of 9 possible bonus pots. The number selected can vary depending on the amount bet, the number of bonus blocks that were hit during the spin, or some other factor. Also, the winning animation has some suspense, as different prizes are pulled out in different quantities, and the amount from each pot is pulled out a little bit at a time. These are all concepts designed to increase the player's excitement at the bonus round.
I know this would take a lot of animation work, the Lobster Larry bonus probably took a couple man-months to implement, but it could be a fabulous selling point, and it would only have to be coded once before it could be re-used for any additional slot bonus system.