I am admittedly a fan of tablets, and over the last 2 years I have owned many of the popular brands, but I am worried that it could lead to a generation less in touch with the field of software development. I conducted a brief survey some time ago that was designed to determine how developers got involved in software development. In almost all instances access to a PC (including Windows, Mac, Atari, VIC20, ZX Spectrum, etc.) preceded the future love of programming and software development.
Is having access to a tablet the same thing? Probably not, in this regard I think a tablet is more akin to DVD or Blu-ray player. A Blu-ray player represented a leap forward in media presentation but it did not provide more access to the underlying technology than lets say a VCR (one could argue it provided less). These very functional devices, like tablets, do not lend themselves to unobstructed free discovery.
PCs (and other programmable computing forms) allow deliberate access to the underlying architecture to recreate, emulate and improve on functions within the OS. This can be created directly on the device you own, for the device you own, and even for others. Tablets continue to be subordinate to PCs in this regard and this restriction actually serves the everyday consumer by reducing complexity, but for the curious and intuitive ten year old on the verge of a future defining discovery, it serves as a barrier.
So as I see PC sales continue to decline my concern for future developers increase. Clearly I am assuming we will programming under the same paradigm as we do today and that will probably not be the case, so as tablets mature (on all platforms) I hope they reintroduce the programming possibilities I believe we are losing.