RT supports limited side loading but those apps would still need to be Modern UI Apps and requires a developer license or Corporate EA, no Win32 Binaries are able to execute in the RT environment. The reason for this, Windows RT is a closed system and that makes a more harden OS less likely to me impacted by malware and code decay, which happens in traditional x86 versions of Windows because of 3rd party software venders changing core OS components (aka - dll hell). Rooting a RT device is against the EULA and thus far has not been done and I believe will prove difficult due to the TPM and UEFI BIOS as these tend to discourage 3rd party boot loaders. If you're looking for more flexibility in a Tablet, look at the x86 or even an Android that can be rooted.