Saeviomagy
Adventurer
If you take your turn, you are guaranteed to take your turn. Total turns taken: 1This is the difference maker between our perspectives; you believe moving to an ally, making a heal check, and then letting them make a pretty serious saving throw is the equivalent of skipping your own turn.
If you help your buddy make his save, you have (usually) a 55% chance of giving your buddy 1 turn extra. Total turns taken: 1 * 0.55 = 0.55.
In essence, it's only worth waking your buddy IF whatever he does will be 180% as effective as whatever you were going to do.
Additionally it is typically NOT a good idea to bunch up in D&D unless you're focus firing a foe.
Now there IS the fact that your granted save has a 55% chance of negating enemies CA against your friend, and so in specific instances there might be a reason to do that, but it's far from a general case.
First: 55% is an unusually high rate of power failure for a competent character attacking a monster's weak defense.When you miss an attack is that the same as being stunned? At least when "missing" a saving throw (a pretty easy hit compared to an attack roll) - you don't use up any of your powers.
Second: you've also lost your movement. There's a decent chance that you didn't actually want to be next to your ally.
Third: It's a rare daily power that has no effect: line, and if your best choice is to use one of those on a 55% chance to hit, while your buddy has a better power to use, it might... MIGHT be worth bringing him back.
But most of all: there are far more interesting effects to use than stunned. Stunned AT BEST swallows up someones standard action for very little drama, tension or interest. At worst, you end up with the orbizard: every combat ends with the party beating the most powerful foe of the encounter to death while its defenseless and immobile.