I'd answer that with metaphysics certainty for you but my Chrystal ball slipped out of its case and shattered into a million pieces.
Seriously, anybody that thinks this stuff can be predicted with any degree of certainty is selling you a bill of goods.
Instead of trying to second guess which interface will dominate the market why not select something that supports multiple interfaces. That way you can choose whatever interface your machine supports. Here's a few examples (
Example 1,
Example 2). Note that some of these drives do not say they support Thunderbolt but there is a Thunderbolt to Firewire adapter available.
Here are a few things to keep in mind:
1. Do some homework. The ones I cited are just the first things that came to mind. That same company for example has enclosures that can handle more drives. You might also find better prices elsewhere on similar devices.
2. Although these devices support RAID arrangements you can have the drives function independently (such as what you seem to be looking for)by making sure the enclosures urges support JBOD (Just Big Old Disk). Most of the multi-drive enclosures do.
3. Some drive enclosures have a funky feature that I do not like. You cannot insert drives which already contain data into the enclosure unless you are willing to erase the drive. because the setup requires formatting the drive. So far I've only seen this in some cheaper single drive enclosures but I have been burned by this a few times.
