Cyclone is indeed a very good spell, but other healers have their own, albeit lesser, forms of CC.
I really wouldn't say Druids are the best healer. They are fairly easily counterable with well-timed switches, all it takes is for the opposing team to not be tunneling retards Of course taking into consideration the average MMO poster I guess I'm not so surprised the poll results are what they are. Plus dispel spam and less than optimal burst healing makes Rdruids have a pretty significant hole in their healing repertoire.
The best healer strictly in the sense of healing output and capabilities would be the priest. Simply the most versatile, with a good mix of cds, offensive and defensive capabilities, and variety of spells to cover all situations. Their weakness is also usually covered by their partners (again, stop tunneling and peel your priest already :P)