Does SSS have any vulnerabilities I should be made aware of?(Shamir's Secret Sharing)

So I was thinking about possible ways to make AES work with larger keys than the AES max of 256, I know it is already secure enough as is, but I thought it would be fun. One of the ways which I came up with was to take the message and cut it into X keys using SSS and ecrypting each key. Now, what I would like to know is if this is a good idea or if its a horrible idea and that I should be sent to hell immediately.

TL;DR
I wanna use AES with SSS to have larger keys than 256-bits. Is this a good or idiotic idea?

^{Sorry for my bad English.}