Sure. I've yet to find a site that allows me to say, I'm in Amsterdam and want to fly somewhere for 7 days in October for less than 500 Euro, show me some options and a facet navigation to drill down further.
It's my most frequent use case, and I strongly suspect I'm not alone.
Have you come across Skyscanner (www.skyscanner.net)? I'm an engineer there, so am a little biased - but this is exactly the type of question we try to solve. Would be interested to hear if you have any feedback/queries!
I have been using http://www.bing.com/travel/ (was Farecast before MS acquired it) for a while now and it has easily saved me a couple thousand dollars on airline tickets. Highly recommend it although yapta does look interesting.
"Can X be improved?" Anyone who says no to that question is being silly. Can't damn near everything be improved in some way or another? Especially something so universally hated as airline tickets...
The bicycle has been constantly improved since its invention and will continue to be improved for a long, long time. For example, engineers and scientists are able to create new alloys that are lighter and stronger than previous iterations.