It seems you would never be able to play it unless all of your heroes generated the same sphere. It might not be so bad if the cost only had to contain a tactics resource rather than have 3 tactics resources from 3 different heroes. My gaming group might actually house rule it as such to make the card playable.

Yeah, as it currently stands, unless you are playing mono-tactics, it is useless. Perhaps you might change it two 2 out of 3 have to be tactics though, as the effect is QUITE powerful.