With increasing demand of connectivity features for different needs there has to be a vast support of services on a phone. I know it isn't possible to contact sony directly through here but the representatives may be able to give feedback and get this feature added. USB OTG can allow u to view flash drive data on ur device and even transfer and manage data through it.
Xperia L does not support USB-OTG. However some models support the USB-host standard (like Xperia S), which allows you to connect USB devices to your phone via a USB Host cable/adapter.
I just tested this with the Xperia L and it didn't seem to work.
