I think it would be a mistake to go to the effort & expense of building an underpass at 11 street without vehicle access, especially since vehicles can cross there currently.
I think improved connectivity for ALL modes of transportation between Downtown & Beltline is beneficial.
As long as we get real sidewalks with real widths (say 3m+) I am all for keeping car access. Car access is important, but the future is more and more pedestrians so the right balance is needed.
I don't know why the City is trying to make 16th Ave. accommodate all these different road classifications in a single corridor. I'm fine with "urban boulevard" improvements through Montgomory because it makes sense given what it has become in that location .
What I would love to see is the City identify a corridor across the north to become an actual freeway to accommodate the TCH. Could be similar to what Glenmore Tr. is in the south. The best corridor I can think of for this is JL Blvd-McKnight. The problem is linking this up with the existing TCH west of Shaganappi/Sarcee. Perhaps Shag or Sarcee becomes the connector heading south to Crowchild Tr. and Crow links up with the TCH west of the city. Sarcee makes some sense as a connector that could run down to 16th Ave. but we all know the firestorm that would start trying to cross the river.
Anyway - that's my dreamworld.
My takeaway is we ended up with these quasi-freeway treatments in North and NW Calgary as each successive freeway plan couldn't be realized or was unacceptably expensive/disruptive or impractical. Rather than "finish" one route, we left it as a weird half-freeway and moved to the next to "solve the problem once and for all".
My vote would be in the other direction, where as we continue to intensify and urbanize we need less quasi-freeways not more. History has taught us that every freeway plan that was ever built to solve the problem once and for all eventually gives way to another that proposes the same thing because the first can't due to induced demand and ever increasing traffic. The result is an endless creep of expensive auto-dependency and congestion that can never be solved by freeways alone. The only way to beat/manage congestion is denser and mixed land uses with a huge increase in non-driving travel.
Have you seen these? 1970s Calgary was dreaming big, some of the ideas you mentioned were considered before. Really cool look at what could have been! From this site:
http://albertaroads.homestead.com/Calgary/plans/index.html
Goodbye Bowness main street and Edworthy Park, hello Sarcee and Shaganappi interchanges!
Probably the most destructive section for both what existed when proposed and what would come in future decades. Looks like two options were considered for TransCanada and Crowchild intersections. Both would have removed much of Banff Trail and Mount Pleasant. You can see one part that was already built in anticipation for this system, in the weird 14th Street and 16th Ave interchange that still stands today.
Deerfoot and 16th Avenue intersection turned out much like what was proposed. The missing part was the freeway on 24th Avenue N and the mega-stacked intersection where Mayland Heights currently is.
NE Calgary really didn't exist much so not nearly as disruptive on this one. Kind of wild to think this was the edge of the city only 50 years ago.
The site also has the more famous and even more destructive Bow Trail Freeway plan. No more Inglewood or Bow River path/park system with that one.
Really interesting stuff. If I can find it, the "downtown penetrator" image is also impressive. With an elevated freeway going between 11th and 12 Aves.