Quick question
 

Can a Shaman make a viable healer for a group at 60? does he have enough healing spells to do so?

Yes, but it's not going to be as efficient as if there was a cleric present, so a lot of the community wouldn't recommend it. I definitely prefer having a cleric in the group, and I am all about weird group compositions. 96 Rez is a crutch that there's just very little reason to do without.

At level 60 a Shaman who has his spells (specifically Torpor) will heal sufficiently in almost any situation. Torpor plus Regrowth plus Cannibalize means the Shaman can go longer than a Cleric can before running out of mana. The Shaman also brings tools such as slow and malo which someone else has to provide if you have a Cleric.

Of course Torpor is a very expensive level 60 spell which not all Shamans have. Complete heal costs a few plat from a vendor at level 39. You can be sure the Cleric will have his most important healing tools while you'll have to ask a Shaman in advance.

Danth

yup as the previous poster said if you have torpor a shaman can be preferable in some situations. not only can they slow the mobs they can haste/buff the melees and also jbb nuke if they have one etc and epic dot etc.

shamans are the preferred healer in most melee / healer duo's however in a full group / raid situation it is hard to beat a clerics cheal

When Velious comes out you will kiss every Cleric's butt to get in your group. :p