I doubt 100k mana was returned, I would like to see the math behind which totems and timers on remaining totems that were present being out at that moment when you used recall. It doesn't count all totems throughout an encounter when you use it, it only counts those presently active when you use it, so 16k each ele totem, 14k hst, and say 8k capacitor totem.... not nearly 100k. Unless the ability is bugged atm, which I could then see why.
As for healing heroic content, I don't think shamans will have any issues. My group isn't fully geared aside from myself really, and I have just gotten lucky tbh with drops. But during Guardians I was top healer around 60k hps the whole night, and some fights peaking 72k hps, not counting overhealing of which I averaged 27% the whole night. So I wouldn't say shamans are going to be bad in heroic progression, just not as well off if people aren't geared/specd/gemmed/reforged right, or don't have a brain about their class. ^.^
HST costs 14,100 mana for resto.
With the glyph giving returns of 100% as opposed to the normal 25%, you effectively gain 10575 mana each time you recall the totem (well not really a gain since you spent the mana to begin, but most people get what is actually meant).
Thus if you recall the totem at the last 1/2 - 1 second (which isn't hard to do by any means), you can "gain" (again not really the best term) 20,000 mana a minute if you use HST on cd. Comes out to about 1600-1700 mp5 if you use it on cd and always recall it right at the proper time. Over the course of a 5 minute fight you could see returns of up to 100,000 mana if you did it on cd.
This is ignoring HTT and MTT, but if you are smart you can drop those while the totem is on CD. Of course the encounter / your raid group's mana is going to dictate when you actually drop these 2, however, and so you don't always get that chance.