Yes, "i wish you good morning" is a common sentence, i don't understand why it has been removed and changed by the "say" verb. I use this app to learn Greek to be able to talk to people in Greece and so far this is more disturbing than anything else.
It takes a lot of time to learn unuseful and complicated words while we don't have thr knowledge to say simple things like "hello how are you".
Confusion should not be accepted in this. "Wish" means something, "say" an other thing and I want to be able to make a distinction between the two without having to think back 10 times.
The important thing is that the English sentence with "wish" isn't correct without an indirect object. "I wish you/him/her/them good morning" is fine, but "I wish good morning" by itself is wrong to all native speakers' ears. The Greek sentence doesn't have an indirect object, so we're left with "I say good morning" as the closest we can get in English to convey that.
"Wish" doesn't always mean something different from "say." How do you know if someone is "wishing" you a good morning unless they say "Good morning!" to you?
In any case, "You wish good morning." is a very strange sentence which I can't make complete sense of as a native English speaker, presumably translating idiomatic Greek (is this the case?). A recipient of the wish is expected in the sentence. Does "Εύχεστε καλημέρα." mean, "You are wishing someone good morning." (with an indefinite object) or "You are wanting a good morning." (wishing for yourself) or "You are saying 'g'day.'" (with speech implied)?
Google Translate provides: Εύχεστε καλημέρα. --> Wish you had a good day. Εύχεστε καλημέρα. --> You wish you good morning. Εύχεστε καλημέρα! --> Wish you good morning! Εύχεστε καλημέρα! --> Happy Day!
Google's robots seem to be suggesting the sentence implies a second-person plural object (perhaps reflexively from this middle-voice verb?) but I'd rather hear from a real Greek.
Sorry for the late response. I don't see any reason for confusion in your examples, however awkward the English might be:
We wish you good morning.= (Εμείς) σας/σου ευχόμαστε καλημέρα. (Addressee=you)
You wish good morning.=(Εσείς) εύχεστε/(Εσύ) εύχεσαι καλημέρα. (No addressee)
I don't know what these Greeks had in mind, but I don't see why they would make such a suggestion.
Wish you good morning = I wish good morning to you
Εύχεστε καλημέρα = You (plural) wish good morning (to someone - unspecified)
There is great difference between the two and, while this might not be something frequently said in English, exchanging pleasantries is a big part of everyday interactions in Greek, so it's good to know ;)