Mélanie Joly seems new and fresh because she's younger, but I don't think she offers anything new in terms of general attitude or core political ideas.
Having square posters with a dark background is just branding to suggest there's something new inside.
I suspect that given time, she'll end up in the exact continuation of past liberal business-first policies, backed by whoever was backing the old ones and serving their interests.
In this election, only Bergeron has a different outlook on things, putting the interests of Montreal's citizens first, and is the only real alternative. Now you may obviously agree or not with his plans, but read them first, you never know!
Another factor, besides policies and ideas, is leadership and the weight to go fight Quebec or Ottawa for decisions made at higher levels which impact Montreal (think Pont Champlain or Turcot), and that's a completely different game.