Well, They've probably rolled the latest bug fixes into the next update, which I suspect will be coming in April.
Technically, we have had 3.3.1, it's now 3.3.5.
I suspect what you're really after is 3.4 or do you think we'll be going to 4.0?
You apparently do not understand how software release numbering works. There is a big difference between 3.3.01 and 3.3.1. The former represents a very minor, specific "fix this particular bug ASAP" patch, whereas the latter represents a much more comprehensive, large patch specifically focused on fixing bugs. Just compare the patch notes of 3.3.01 and 3.0.1 (and 3.3.02 with 3.0.2, etc).
A new content patch would be 3.4, which TBH is not a priority for me personally. I much rather Frontier fix the existing code before adding new code. There was plenty of features added to 3.3 that I find enjoyable except for the bugs. Of course there are bugs that are over a year old that I'd love to see fixed as well.
As for 4.0 vs 3.4, technically Frontier could use either number the next new content update. A new year may warrant a new major (4.0) number jump. FWIW, the software patch numbering system is not very intuitive, so I don't fault people for not understanding it.