E-ink should hopefully evolve and improve its game to be more readable and responsive, or it should get replaced by reflective and transmissive technologies that can do its job better. It is quite strange to think that currently available tablets are in any way targeting dedicated ebook readers, which are mainly a growing fringe novelty with the current state of the technology.
A tablet designed for ebook reading that isn't just a whip-together project to jump on the bandwagon (as was typical of 2009) will try to resolve many of the issues related to power conservation and daylight readability. Some may take advantage of e-paper technologies like Liquavista, E-ink (if it improves), Mirasol, and reflective LCD, while others may use transflective LCDs for reading-heavy applications or dedicated emissives like LCD and OLED for less reading-oriented purposes. It seems to me that many of the manufacturers and marketers out there know the marketing power of the "paperlike" hype a crappy screen like old-school e-ink was able to wield. Part of that appeal will need to be absorbed into new marketable reading-oriented tablets.