It is ABSOLUTELY not without problems if it shall work with all versions of MySQL – both those that use COLLATION and those that do not.
Up to 4.0 it would be not problem to include a DEFAULT CHARSET= xxx.
but with 4.1 ++ it must be DEFAULT CHARSET=xxx COLLATE=xxx_yyy, but the COLLATE=xxx_yyy must be with each column definition.
From MySQL 4.1 there are so many “encodings” (your expression, not a MySQL expression) if you consider each COLLATION variation an “encoding”, that I believe it will be very confusing.