360 manas worth of heals. That heal up to 230 each, so 720 (+135% AP) worth. With 1000 AP. This goes up to 1350 or 2070 health regained. Places one every 12 (or less seconds) and must wait 10 seconds to be the full amount.
For 300 manas worth of heals, Taric heals 220 each, so 660 (+30% AP) (+15% Taric's health, so if Taric has 3000 health, that's 450). So, 790 (+90% AP). Taric also gets healed for this amount. With 500 AP, Taric heals 450 bonus, or 1240. Must wait 18/17/16/15/14 seconds (or less) to heal again, heals can go to 16/15/14/13/12 seconds with passive, and go down by 6 seconds in total with all abilities used for 12/11/10/9/8 (or less) seconds for reuse.
That means, for every 3 heals Bard uses (at max level and waits for max heal) Taric can heal (at max level with passive) 5 or more times, sub totaling to 1100 (+150% AP) (+25% Taric's health) worth of heal. So with 500 AP and 3000 health, Taric can heal up to (+750 worth in AP) (+750 in health) to equal 2600 health that Taric can heal. And this is the least amount of possible heals.
Besides, the totems must me stood on to work, anyone can come by and take one and whoops, your down one for your ADC. Taric's are point and click. Sure, Bard can do that too, but it only does the small effect. And leaving a totem I can come by and step on isn't that safe. As someone who's played Bard a lot on the PBE, he's only stronger than Zilean, who to me is possibly the weakest support right now. His kit is made for supporting, +8% EXP, 1.1 to 1.5 second stun, bonus MS or enemy slow, and revive, but his early game is weak as ever. +8% EXP is somewhat useless as is. I wish Zilean had a more useful passive.