To Vernon's credit, he's the classic 'hometown boy does good' story. He grew up in Calgary, as I recall he played for the AJHL Royals, made the NHL and backstopped his hometown team to their only Stanley Cup victory. He eventually got traded and won a cup with Detroit, their first in 55 years, he was awarded the Conn Smythe for his effort.
On the other hand, was Vernon good enough to be 'banner worthy?' This is supposed to be for the best of the best, not just a good goalie, or even just a winning goalie. He has to be a GREAT goalie. Fairly or not, my two biggest memories of Verny are Gretzky going slap-shot roof daddie and Roy and Vernon teeing off on eachother. Vernon had a reputation for giving up bad goals, and also for not making the important or 'key' saves.
And what about the other Flames retirees that were great for the club? We must be planning on retiring MacInnis' jersey (it would be a travesty not to) and I would hope the Flames plan on retiring Fleury's. Should Vernon's numbers be raised before the aforementioned Flames?
My conclusion? Vernon is good enough to have a banner name, even if it's maybe a bit premature in light of other Flames that have been great.