Ok, let's get the facts straight here.
Vigorous Spirit: 5 mana, 1 sec cast time, 4 sec recharge. Everytime target ally attacks or casts a spell, that ally gains 1-11 health. (30 seconds)
Healing Breeze: 10 mana, 1 sec cast time, 2 sec recharge. Target ally gains 3-8 health regeneration. (10 seconds)
We will assume 12 in healing for the comparison.
Healing Breeze gives +8 regen, which is 16 HP/sec.
Swords and axes have the fastest attack speed, at 1 attack every 1.33 seconds. I think that's right in line with the truly spammable spells, like Flare, but I'm not sure on that. Regardless, let's compare sword use over 4 seconds, which would be 3 attacks.
4 sec * 16 HP/sec = 64 HP for Healing Breeze.
3 attacks * 11 HP/attack = 33 HP for Vigorous Spirit.
Even with speed-boosting stances like Flurry or Tiger's Fury, you aren't going to make up that gap. And remember this is with the fastest of weapons; if the target is using a hammer or bow, it's going to be an even bigger gap.
Healing Breeze is a much faster heal, has half the recharge time, and it doesn't depend on the target doing anything. Vigorous Spirit lasts longer and is cheaper.
My El/Mo routinely throws around Vigorous Spirits like they are pennies. They are so cheap and last so long that I can pretty much keep 3 allies with it at all times and not even drain on my mana reserves. It's almost a throwaway spell. Just cast it a few times in advance of a fight, probably on warriors, and it'll make your life easier (unless there's an enchantment breaker on the other side, in which case neither of these spells are a good idea).
In any event, these aren't mutually exclusive, so why not try to keep both of them up on the same person?
