Manufacturers' battery life claims are seldom based on real-world use cases; at the end of the day, battery life is dependent on how you use the device.
So even if you had
zero USB ports, this does not immediately guarantee better battery life than a similar device with 1 or more USB ports. Again, it all depends on how you're using the device. Attach a USB hub with all sorts of data/CPU-intensive peripherals to your single-port device and what's that going do for you versus someone with the two-USB version of the same device and is using less-intensive peripherals on both ports?
I can't believe that the lack of a second USB port was driven even in part by the drain on battery life. I believe that it had to be mainly driven by engineering. But if for some reason just having a port--even if unused--eats away battery life, then I take back all that I stated above.
Having stated all that, though, I for one would jump for joy to have a second USB port; however, I do not understand what the big deal is for people to buy a hub. I have 10-port hub for home when I am "docked" and I have a 4-port mobile one that I use when I'm travelling.
The reason that a second port would be beneficial is that these days people own a non-Bluetooth device that needs to be permanently connected (keyboard, mouse, fingerprint reader, etc.) and said devices can also be in the same category as the Surface: Mobile. So for those of us who have such devices and are mobile with the Surface, yes, one USB port is restrictive but, again, I don't see the big deal in using a mobile hub.
Nevertheless, there definitely is value in having two ports. Beyond two, for sure get a hub; but in today's world, two should be the minimum for such a device as the Surface Pro.
For those who say Bluetooth, sorry, but it is never always the (best) answer. As an example, I tried/used several Bluetooth keyboards in my "docked" profile at home; eventually, I gave up and switched to a USB receiver-based keyboard. Though I am perfectly happy with my Type Cover while mobile, imagine if I were not and relied on a mobile USB receiver-based keyboard. Surely you can see how beneficial it is to have one port dedicated to our most important always-connected peripheral and then the second port would truly be used for the as-needed devices.
The Surface Pro
1 replaced my ThinkPad--not the SP2 or SP3, but the SP
1. Now Microsoft is marketing the SP3 as "the tablet that can replace your laptop." So it should come as no surprise that owners want laptop functionality from their Surface Pro.
For me, though, the Surface Pro is still young and I am more than happy to make compromises in the meantime. It really is no big deal to use a hub; there are numerous varieties on the market from which you can choose that best suits your needs.