I firmly believe that shrines need to be removed for two reasons: First, it is a mana sink, pure and simple. It’s quite clearly the druid equivalent of a collective mage ‘brains’ spell, for which I’ve already expressed my distaste. Secondly, it creates difficulties in balancing the class. A player’s combat and spell power should not be limited to the numbers of your class available to contribute to a mana sink. As no one is prescient and perspicacious enough to determine future playing trends, one would be unable to effectively tweak druids as necessary, thus obviating druid shrines.
In regards to Tyrande’s summons idea, different totems could have different effects in regards to the summon spell. Personally, I wouldn’t want druid combat to revolve around summons, as this is too reminiscent of necromancers. Bat-totem Druids might summon a swarm of bats that increases in number in level. Bats could cause debuffs like confusion and fear. Snakes cause fear, poison and entanglement, etc. It’s limited only by your imagination.
Also, I think the easiest approach would be akin to the Cleric/Pally bifurcation that Belly, praise be unto him, rahmatallah, peace upon him, is working on. A certain set of powers is available to all druids upon classing. After 10th level or so, the druid chooses a totem, unlocking shapeshifting/summoning powers and augmenting powers previously learned.
An interesting thought I had would be a mini-crafting system, specific to druids (sounds like it might work for barbs, too) which allowed them to use sinew, bones, and teeth of their enemies to create talismans (apart from normal wearable slots) with beneficial effects. Perhaps these talismans can be made stronger through the use of barbarian skins and heartblood. This could even be used to make barbarians and druids ‘paired’ party members, like priest and paladin combination.