Nobody was really complaining for the huge ressources taken by Kazaa lite because Kazaa was a closed protocol (gnutella is open and many people check the traffic for irregularities). Also KL was liked by the P2P apologists while Sharman (new owner of Kazaa) was hated because of many spywares. The creators of Kazaa (the protocol core still in use) haven't touch to the protocol since Kazaa 1.5 and they are pure geniuses: they made Kazaa into a performant protocol (in 1 year) while gnutella only reached and outpaced Kazaa since fall of last year (3 1/2 years in the making). Now they are working on Skype another internet jewelry. Did you know that in kazaa 1.5 they limited the number of results to only 50, and only later they let users get max 200 results? They did this on purpose, their protocol, routed by big ultranodes (users very fast connections with up to 10 000 leafs) was limited by the numbers of searches routed. At some point too much searches were performed, and the performance decreased a lot for all the network.
Since Sharman doesn't have a clue about the fasttrack protocol, nothing effective was done and fasttrack is dying
But others will take it's place, c'est la vie.