But CC-BY is allowing this. Maybe CC-BY-SA would be a more GPL-like flavor of CC.
Yes, CC-BY allows modification. IIUC CC-BY-SA would preclude any more than "fair use" quantities of material anywhere that is not itself licensed by CC_BY_SA. For example this might preclude use of newsletter articles on software blogging sites if they have non-CC-BY-SA licenses. So I am not in favor of CC-BY-SA.
If using CC-BY how should attribution be required? Perhaps "Geany newsletter team" and (if online) link to Geany website.
I don't think NC or ND is making any big sense.
Agree, the point of the newsletter is to get distributed.
Cheers Lex