Stella is played by former Eastenders star Michelle Collins and Karl is played by former Taggart star, John Michie. I have only a little exposure to Ms. Collins and none to Mr. Michie since I have only seen Eastenders sporadically and not seen Taggart at all. He looks a little bit Danny Baldwinish, don't you t hink?
I'm dubious. I don't really want to see Southerners behind the bar so I'm hoping they can both pull a Jessie Wallace and put on a credible Northern accent. There have been a lot of accusations from commenters here lately that Phil Collinson is making Corrie too much like Eastenders with grim storylines and this may backlash even further. Coronation Street is a soap that reflects Northern life and it's people and it shouldn't end up being a clone of Eastenders.
I'm willing to wait and see, and willing to give them a chance, but they've got pretty big shoes to fill and high expectations to meet.
Edited to add a few comments streaming from the ITV Twitter page with quotes from Collins and Michie:
>>John Michie: "...I am from even further north so it is the only soap for me.” #Corriebignews