When someday the skytrain comes to the north shore, should there be a new line or a extension of the Expo line?

these are pros and cons for extending the expo line or a new line on iron workers from metro town

Pros for the Expo line :

There would be service from the North shore to Langley

The expo line will become one of the longest metro lines in the world

Cons for the Expo line :

The expo line would be over stretched and will need a lot more capacity to keep up with 5 min service

The extension will have to use the same trains as the Expo line.

Pros for a new line :

There can be different trains run on the line

It will create a way out north from Metro town

Cons for a new line :

Interchange with the expo line, also will take more time (for west van)

a new bridge will cost a lot (same with expo)

less efficiency than through running trains.

Maybe do 2 lines across the Inlet? Expo from Burrard across lions gate, New line across iron workers (both above the traffic lanes), what do you guys think?