Tangle's story arc in Trial by Fire was about how she needs Whisper in her life. She's a buoyant and energetic person, but she's also rudderless on her own. Left to her own devices she'll just go with the flow rather than chase her dreams.
(see the status quo of her life at the beginning of Tangle and Whisper or her aimless milling about in her job at the Restoration pre-Trial by Fire)
She needs someone more grounded and focused to guide her, meanwhile Whisper needs a little more light in her life. Tangle offers an optimism that helps balance out Whisper's much more grim perspective. Their two characters mesh together honestly really well, and I think they'll be a long-lasting team.
They help fill in where the other is lacking, and they can be there for each other through the rough times. Issue 59 was a good example of this, where Tangle was able to help set Whisper at ease and reassure her.
This is all to say that yes, Tangle does need Whisper. The two of them work together so naturally and it feels like they were made for each other even as I'm pretty sure they weren't literally made to go together!