She may be able to heal everyone, but can she keep the whole alliances chakra levels from depleting like Naruto can? No she can't, and one could easily argue that, that's just as important than the healing aspect, he'll you could say it's even more important, because once your chakra starts depletings you weaken, slow down, and can be more susceptible to taking damage this way.
Also I don't think anybody feels threatened by Sakura. We all know for a 100% fact shell never catch up to our favorite main characters in overall abilities, power, and speed. Naruto's sage mode strength is far greater than Sakuras current strength, also Sasuke's Susanoō strength is as well.
So nobody feels threatened by Sakura. Also should know that that's a very childish thing to say since it's an anime, and people can't feel threatened by a manga character.