I think that Current Day and Current Month should return integers. This has numerous benefits including resolving language issues, allowing calculations dependant on month of year, etc.
If required, the name of the day / month could be pulled from global attribute lists using the integer of the day / month to return the appropriate text.
I'm not sure how returning a 'season' could work because seasons vary depending on the part of the world in which you live. I think it's the sort of thing that would be determined by the designer, rather than being an inherent part of Stencyl. It would be very easy to code, e.g.
[if month > 12 and month < 2 then season = "summer"], etc.
Jon, with regards to the code being 'trivial to add', when do you think you could implement this? By the end of this week would be great, as I have a couple of applications I would like to create using the system time / date. Only joking of course; I was thinking of maybe allowing you two weeks!