Depends on the quality of debuff you're referring to in your question. I do all of those things on my paladin, when I need to do so. Stun/pacify/MR debuff are part of my standard spellset (and root and reverse damage shield, though you didn't mention that). Anklesmasher for snare if I really need it, Hammer of the War Machine for slow (or Helix of the Undying if the mob is undead), Journeyman's Walking Stick for additional tash, Cracked Claw of Zlandicar for cripple, and others. A few of those have better versions if you are a raider, which i am not. I view debuffs a little differently than most people do, though. I don't use them for the actual benefit most of the time but, rather, as a way to overwrite/block the mob from using their own buff if they have them (haste, ds, etc.).
Yes, druids have excellent debuffs. In some cases they are nearly as good as slowing. (It's more a question of whether the druid memorizes and casts the spells regularly.) We have a stun nuke which is resisted often and we can pacify in outdoor zones.
Given that snare is has been a non issue for years I'd say Enchanter is your best bet. Otherwise, you'd need to list them out in order of priority that you want them to get better answers.
Indeed. Ranger 1.0 was always a must have for me back in the day. And I don't recall, but do their paci/lulls only work in outdoor zones?
mostly outdoors till 85 (?) We get a harmonious arrow spell AA and we have this cool one that knocks back the mob so folks can run away fast. Our debuff we get early on with nullify magic, plus our epic for slows, and finally our looks are just stunning! Or any weapon/aug that does that in the bandolier with the epic.
Bards can snare, pacify, stun (bellow) and to some extent debuf. Just depends on their song lineup, and gear that have procs on them. With the right gear, a Cleric could do all of those things as well. Biggest thing they are missing is a snare spell.