Personally, I won't answer a question "should I upgrade", because all versions may have flaws that will never be fixed, and I don't want to advise someone to upgrade, only to find it has a flaw that the user used to rely on, but now doesn't work.
That said, for me, the main question is whether you need 64 bit processing, if, in v11 you regularly hit an out of memory error, or failed renders, then you need 64 bit, something like TC v21 (which is also the last version to have Lightworks rendering built-in). V19 was the first version to go 64 bit and one or two things didn't work as well as they should (for me at least).
If you never get out of memory, or failed renders, then 32 bit is fine.
There are plenty of the newer things that I miss whenever I open v11, but that's simply because I have got used to the newer tools.