I think that the journey is half the fun. We spend too much time thinking we have to be max, but especially as a self-contained group, enjoy the journey to the top! It's a different world, and a fun and beautiful one. I wouldn't recommend going Heroic.
I love your group, personally. War/Cleric/Enchanter/Mage/Wiz/Open is a great caster group and I like your thoughts.
What this comes down to is what you are looking to accomplish. Are you looking to enjoy the lower levels and have less problems with death? Then perhaps a melee group would be better, since they are more durable and higher dps until sustain evens out higher (~70?). Are you looking at something really stable you can more set-and-forget? Then it might help to have another healer, since your group doesn't have a backup now at all. You have a backup tank (pet), but not a backup healer. If the Cleric goes down, so does the warrior.
Personally, if you just want a stable group for the higher end, I might consider filling out your group as Cleric/War/Bard/Mage/Wiz/(BL/Necro). The BL/Necro fit in the group as different classes, with a bit more durability (necro to FD rezz the group, or BL to simply have "2" more tanks). The biggest thing that I think your group is missing is a puller, which is why I suggested swapping in the bard. I know the enchanter is extremely common, but its just not something I would like to use for chain pulls boting - too dangerous.
I've actually been thinking about this quite a bit lately, and I think my next group (which will be starting at 1) will be:
Tank - Haven't decided completely yet. Warrior is great, but I like the AE agro of SK later.
Cleric - Need great, consistent heals.
Druid - OK DPS and backup healer
Mage - As you said, good DPS and backup tank
Enchanter - Most consistent/powerful CC plus good spellcaster boosts (another vote for SK)
Monk - Need a puller, and bard would be redundant. Not a ton of synergy, but also another good durable backup tank
I think this group will not level extremely fast, especially in lower levels, but will be extremely stable. If the tank is an SK, this is also a great setup with healer/SK/MageDS to powerlevel others if you are interested. I don't think there is a camp in this game this group couldn't do.