Is this team good enough?

The team looks fine, but Gunnthra specializes in eviscerating enemies that are debuffed, so maybe try to get a unit like Saizo, or Sothe from the Sacred Stones banner for example. Or try to hook her up with some Ploys (and higher resistance).

Two amazing dancer, two Legendary heroes, the only mounted bow, and one of the better sword cavalry units in the game? You'd be foolish to reroll!

I would stick with it.

I’d say go with it.

You have more than half way a great Horse emblem team. Fjorm its fantastic. Tharja and nino eventually could be 5* and bladestorm most units in the game. Kagero infantery killer. P-azura is great