SLU to Capitol Hill Gondola
With Link running mostly north to south, what's the best way to serve neighborhoods to the west and east of the line? The highways (I-5, SR-99...) run north/south, too, and Seattle's hills get in the way. Gondola technology might be a good way to address this issue. Gondolas' ultra-high frequency speeds up transfers, and grade separation provides reliability. East-west trips are usually short, so a gondola's limited speed isn't an issue. While South Lake Union (SLU) and Capitol Hill have been booming and growing significantly, bus route 8 has been struggling to make its way up the hill, and gets into severe traffic congestion along Denny Way causing long delays. A decade ago, Matt Gangemi and Matt Roewe, an engineer and architect respectively, proposed a gondola line connecting the Sculpture Park, Seattle Center, SLU, and Capitol Hill along John Street. Connecting the recently-renovated waterfront and Seattle Center's cultural opportunities with the SLU tech centers and housing and Capitol Hill nightlife should be part of the mayor's and Chamber's plan to revitalize downtown Seattle and make it more attractive to tourism.
Recently Ross and I discussed various alignments. It would be nice to serve the center of Seattle Center directly akin it did during the Seattle World Fair in 1962. Running along Thomas or Harrison Street might be better than John Street. You could also extend the line beyond Broadway to serve Kaiser Permanente hospital and the business district at 15th Ave E.
One way to build such a gondola line would be to add another lid over the waterfront railroad for a waterfront station. From there it could continue to Denny Way along Eagle Street, and then along 2nd Ave N into the Seattle Center with a station between Climate Pledge Arena and the International Fountain. This would be close enough to serve both the Arena and other event spaces further north. From there the line could go east along Harrison Street with potential stations at Dexter, Fairview and Broadway before reaching its end at 15th Ave E:

If you don't want to cross the Sculpture Park, you could go along Broad Street and 3rd Ave N passing by the Chihuly Garden. Not quite as central for the Seattle Center, the station would be closer to the Monorail terminal:

If you would rather serve the Bell St Conference Center / Cruise Terminal, Belltown and Amazon offices instead of the Seattle Center, you could start at the Cruise Terminal and continue with a few stations along Bell St (Link stations in red) and continue along Olive Way:

All of these lines follow existing right-of-way. Stations could be built above intersections or may need some extra land. In 2015 Matt Roewe (Via Architecture) worked on a preliminary design for a gondola between the ferries wheel and the Convention Center along Union St. Even though that short line was never built, his design shows how a gondola could be integrated into an existing downtown street:

Station design may look similar to what San Diego had considered a few years ago, or you could borrow designs from gondola lines in Mexico City, Haifa or Paris (under construction).
Like how RapidRide G transformed mobility along Madison Street, any such gondola line could make the Denny corridor far more attractive. Connecting the waterfront, SLU, and Capitol Hill more reliably and frequently with a gondola would be a major improvement to people's transit mobility for both neighborhood trips and as a feeder to Link.
PS: For my prior gondola posts, check out: Bellevue College and Issaquah.