I'd hire dogs and have them sniffing around. They'e infinitely more effective than Trained Shoe Analysts at finding contraband where ever it may be hidden -- dogs know that shoes aren't the only place where interesting things can be found.

I'd lenghten the rollers leading into and out of the bag check machines. Aside from the shoe shuffle the major source of delays that I see at screening is that the whole process of getting your bags up and onto those tables, filling the bins and then moving them along (and navigating around the piles of bins...) is a cluster-puck.

I'd have the TSA start paying attention to the rest of the airport. As tempting a target as the screening machines, and baggage belts may be I think that there are other areas that they should be guarding. Why, for instance, isn't there a requirement that there be a TSA person greeting every catering worker and checking ID when they load the pretzels? (Of course that's another thing that dogs would do a better job of but I digress...)

I'd drop the boarding pass requirement. Let anyone who wants to put up with it go through the checkpoint.