When people first started chatting about it, I didn't exactly believe Serato was going to leave out a big chunk of their current market of SL1 and TTM57 users, which my guess is currently 90% of a Scratch Live users in the world. But after reading that it is true, I sat and thought about it again and I can see from a business point of view why they would do this.
While the official reason is because the SL1 and TTM57 soundcards have outdated technology, specifically their audio resolutions, I can't help but think that this is Serato's way of selling more of their newer units like the SL2, SL3, and SL4 as well as their mixer line of the Rane 61, 62, 64, and 68.
If you think about it however, and this is entirely my own personal speculation, I don't think this is entirely unfair. The way Serato's business model is, the software is free, and the purchased hardware propriety to the software is how you pay for the software development. As we all know, preowned SL1's and TTM57's can be hot commodities amongst working DJ's along with used Technics turntables. Some of these 57's and SL1's can make it to third, fourth, fifth hand, and so on. Serato is not exactly making a profit on used Rane hardware being resold. While it sucks for the legacy equipment users, I think this is their way to clean up second hand market that Serato sees no penny, which like I said, counts for what I believe is 90% of the Scratch Live world.
If there's one thing I expect in return for this inconvenience to my 57 and SL1 colleagues, it's faster development time from the Serato developers. No more late updates. Serato seemingly had quite a plateful this past year. When Serato DJ was released, updates for controllers were delayed from a promised Spring time to the Fall. The update that I waited over a year for was the HID support for Scratch Live and the CDJ-2000Nexus. HID is technology that was developed as a collaboration between Pioneer and Serato no the original CDJ-2000 but was strongly delayed with the Nexus.
I am not exactly a Serato only, or a Scratch Live only and I am always exploring the CDJ and Traktor platforms as well, but to the SL1 and TTM57 users, you have till 2015 to upgrade. If you bought your gear used, that means all the software development updates you enjoyed over the years you basically received for free. I'm not one to empathize with a corporation, but I can tell they have been falling behind. In the bigger picture of things, I predict some awesome developments from Serato's direct competitor, Native Instruments. A dual USB Z4 mixer would be nice.