There’s no reason that GNU/Linux cannot serve well on tablets. It’s a universal OS.
“Japanese firm Systena Corp. announced the first Tizen-based tablet, which also appears to be the first Tizen product of any kind. The unnamed Systena Tizen tablet offers high-end features including a 1.4GHz, quad-core Cortex-A9 system-on-chip, 2GB of RAM, and a 10.1-inch, 1920 x 1200-pixel display.”
Whether GNU/Linux can make a dent in the tablet market under the wildly successful Android/Linux showing is doubtful but in the harshly competitive market manufacturers will use GNU/Linux to distinguish themselves and leverage the huge resources of FLOSS to demonstrate better price/performance. FLOSS against FLOSS may not offer much price advantage but GNU/Linux running natively may have some advantage in performance. Whether touch-lovers will notice remains to be seen. I expect that users will love the better multi-tasking performance of GNU/Linux and grow to appreciate that tablets can do more than show pictures.