Once again I have mixed feelings, to probably no one's surprise. Traditionally in D&D, the cleric was a more martial or militant representative of a divine order, not necessarily a run of the mill priest, but an adventuring focused version of such an organization. They did not even receive spells until 2nd level, and were expected to be front line combatants along side the party fighter. Thus the heavy armor and a useful weapons list. So the Life cleric is probably slotted into this type of role; or at least, that is what I believe to be the intent. But, as has been pointed out, clerics did not get quite as much blasting power from their spell list; it was a bit more support focused. Sure you had Spiritual Weapon (very good in 5e), Flame Strike, and Blade Barrier; but most of that was limited to higher level and there was greater demand for healing placed on their spell load out. Druids where differentiated partly because they had more blasting earlier than clerics at the cost of less healing/protection. Now it seems that the cleric is, or at least can be, more of White Wizard type, depending on their spell load out, damaging cantrips and all.
As for the diversity of the sub-classes, I think they are at least as differentiated as the various wizard sub-classes, though others may disagree. I'm not one to pine for the halcyon days of 2e specialty priests, and it seems to me that part of the problems the class struggles with are related to trying to satisfy an ever greater diversity of concept, while still keeping to the traditional role an adventuring cleric is supposed to fill. What with Bards, Sorcerers, Warlocks, & Wizards now, it can be hard to fill a niche.
