There is sufficient means of healing to cope without a healer, albeit you will be slightly limited. There is no real need for CC. People that have played EQ sometimes fall into the mindset that they "need" a warrior, a priest, a mage, a paladin or warlock, and one other. The truth is 5 of any class is fine. Play what you want to play.
What classes bring to the table:
Warrior - tank and damage. Most effective tank. (and more entertaining than an EQ warrior.)
Paladin - secondary tank and provides heals and rezzes.
Hunter - not really sure yet, we only know they're ranged and use animal pets. An archer beastlord, effectively.
Rogue - highest melee damage, but poor defense skills by contrast. Can go stealth, and use a pre-emptive mez called sap while sneaking.
Shaman - horde only, so I can't tell you much. They can melee and heal, but neither is their primary purpose. They summon elemental totem to provide local area effects.
Druid - respectable healer, only modest damage from spells or melee, but a good support class. They can also shapeshift into a bear or a cat to act like a warrior or rogue, respectively.
Mage - nuke masters, but they also have the one mez spell, sleep. It should be noted that sleep only works on one target at a time. Additionally, they can summon no rent food and drink.
Warlock - versatile caster pet class, with a CoH ability that requires two other group members present to participate in the summon, and can also create soulstones that allow a person to rez themself once.
Priest - healing class that has an instant cast rune as their class-defining ability. They can create some decent spell damage when they want to, and have a number of utility spells.
An "ideal" group if you insist on having one, would have a warrior tank, a priest to heal and rez, a paladin as back-up for either of those roles, a mage for DPS and CC, and a warlock for utility. There is no reason to demand this, however, as rogues and druids provide plenty themselves, and having two of one class is not a travesty either.
Only the exceptions can be exceptional.