Touch interface will encourage contact-centric email approach

'Touch' interface users are good at prodding things with a fat finger, and dragging and dropping items. Typing is less convenient than on a device with a 'proper' keyboard.
There are three immediate examples that show where contact-centric email benefits a 'touch' user more than a user of a regular desktop computer:

1. Composing an email to a given contact is conveniently a click on a button by their name, business card popup, or in the contact entry itself.
2. Adding addresses to new emails or replies can be supported via drag-and-drop from the contacts pane
3. Searching for emails based on an email address can be done with a single click on the corresponding contact

For each of these it is common for PC users of existing mail applications to resort to the keyboard (and email client developers have worked hard to enhance the productivity of this). But a touch user might prefer drag-and-drop, and for this to be effective you really want the contact list readily available.
This post isn't intended to suggest contact-centric email is a slam-dunk obvious preferred solution for touch/tablet users, rather to suggest they might find it more attractive than PC users.