Does MagSafe 2 T Connector get really hot when charging?
Yes. In my case, my new MacBook Pro Retina 13" MagSafe connector gets insanely hot but once the charge level reaches above 50% or so, it starts to cool down and then stays lukewarm. 

The best solution is to not let the Mac's battery discharge too much. It also doesn't make much of a difference to the heat level if your Mac is on or sleeping as the heat level in both cases are similarly high.