It's a toss-up, especially if the group is going to be WAR, CLR, ENC, DRU, BST, BER ... the Druid and somewhat the BST will benefit from what the enchanter has, while the zerker and somewhat the beast will benefit from a bard.
What I think would push that group over the edge, though, is an ENC's CC'ing ability is just top notch.... no other class can get even close. If the group is otherwise not fully optimized towards melee or casters, then I would always default to the best class for the "other" stuff. In this case, the enchanter is the best for the "other" stuff (cc).
This is a sample of 8 songs bard could keep on this group and one that pops pretty frequent. He would be adding to spell damage, overhasting, increasing the chance to triple attack, flurry, pet's chance to flurry, increasing ac, str, attack, min hit damage, hit damage, healing, increasing the chance to critical heal/hot, and increasing regen. That is increasing damage, healing and tanking. His mez does not compare to enc, but he can pull and fade. I know about their haste/attack buff, mana regen, runes, illusion with life proc, Visage buffs, and Aura. They can do more for a group with aa's abilities and buff. However, i don't know what and how. To me, he has enc beat as far as what he can add to the group. Can you give a list of what else enc could do? I'll look them up and compare. It would come down to how much dps they can add to group + how much dps they do. I also know little about their debuffs.
all of these stacks excepted the over haste obviously
songs
1: Increase Spell Damage by 31% (Before DoT Crit, After Nuke Crit)
2: Increase Melee Haste v3 by 25%
10: Increase Chance to Triple Attack by 25%
11: Increase Chance to Flurry by 22%
12: Increase Pet Chance to Flurry by 28%
2: Increase AC v2 by 261
1: Increase Melee Haste by 60%
2: Increase STR by 279
3: Increase ATK by 179
4: Increase Damage Shield by 127
6: Increase Min Hit Damage by 41%
12: Increase Hit Damage by 5%
1: Increase Spell Damage by 45% (Before DoT Crit, After Nuke Crit)
2: Increase Melee Haste v3 by 25%
10: Increase Chance to Triple Attack by 40%
11: Increase Chance to Flurry by 6%
12: Increase Pet Chance to Flurry by 35%]
1: Increase Chance to Critical Heal by 25% up to level 110 (lose 10% per level)
2: Increase Chance to Critical HoT by 25% up to level 110 (lose 10% per level)
1: Increase Healing by 12% to 13% (Before Crit)
9: Increase Current HP by 202 per tick
10: Increase Current Mana by 134 per tick
11: Increase Current Endurance by 17 per tick
1: Absorb Spell Damage: 100%, Total: 10
2: Increase AC by 87
3: Decrease Offhand Damage Shield Taken by 105%
4: Increase Chance to Resist Spell by 15%
aa every 3 or so min
Target: Caster Group
Duration: 60s (10 ticks)
1: Increase Chance to Critical HoT by 13%
2: Increase Critical Hit Damage by 13% of Base Damage
3: Increase Worn Proc Rate by 300%
4: Increase Chance to Critical Heal by 13%
6: Increase Chance to Critical Nuke by 13%
7: Increase Chance to Critical DoT by 13%
11: Increase Critical Nuke Damage by 13% of Base Damage
13: Increase Hit Damage by 13%
14: Increase Spell Damage v4 by 130% (Before DoT Crit, After Nuke Crit)
15: Limit Max Level: 110 (lose 100% per level)
16: Limit Type: Exclude Combat Skills
17: Limit Class: ALL