My vote is to keep them around for 2.8 and 2.9 but say goodbye after that.
Again.. it won't be easy for us, but who said progress ever was.
+1 for dropping ZClasses as soon as possible (IMHO 2.10 is a good target), but before that, some comment in REALLY BIG LETTERS should be made in the ZopeBook:
"Don't use ZClasses, because you'll get into real trouble when using them, deprecated or not ;)"
Many "Zope-startes" read the ZopeBook and start over and over again with ZClasses. So we should start to "deprecate" ZClasses in the ZopeBook anyway.
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