I know this likely isn't feasible, but my ideal scenario would be to build a smaller stadium in Roundhouse Park (re-route Bremner north if needed). Then demolish the Skydome and build a new park in it's place to replace Roundhouse.
The plans to build a new stadium partially to the south (over the existing parking lot) don't make much sense as it would require the team to re-locate for probably 2-3 seasons.
I really hate the Portlands idea, there will never be good enough transit serving that space, and the team's attendance will ultimately suffer (once the new building aura wears off). If they have to go somewhere else, I would much prefer Exhibition Place somewhere. At least in the future it will have a stop on the Ontario Line, it's serviced by GO, and is still within walking distance of many people. I'm sure there are people smart enough to design a stadium that could mitigate the wind factors.