Frankly, I don't think this is the best use of MagSafe. Considering Apple essentially decided they didn't even need to include a port at all except it was the most efficient way to charge it, the main way to use MagSafe is for charging it. So data throughput is not really a consideration.
Indeed, if you did want to plug a peripheral into the USC-C port, I can see doing it on the desktop, and daisy chaining the power out of your dock. That way if anybody trips over your cable, it doesn't snap off your data mid-transfer. Besides, people are rarely ever going to run a long cable from their MacBook to a peripheral that puts the Mac in danger, and again you wouldn't want that cable popped off during a data transmission. MagSafe was designed for power, and that's where it should stay. There are no MagSafe data ports now, and I don't see any reason to monkey with it now. If Apple had thought this was a good idea, I'm thinking they would have been the first to introduce it. What Apple is counting on here is that most people only plug their Macs into power. And MagSafe makes that incredibly easy.