I hard disagree with points #2 and #3, but it depends on your comparison city. Coming from Europe, Asia, or New York, I can see your point. From Australia, NW, or the Americas, then I respectfully disagree.
Vancouver has an amazing transit system, comprising of trains, buses, and ferries. It is all connected together, which means you don't pay separate fares either, and most of the major things are very transit accessible. But the key is to know what you are looking for.
So lets start with this (Note: we refer to the rapid transit as "skytrain"):
The CANADA LINE train goes from the Airport to Downtown vancouver. It also goes to Richmond (a very asian centric area). Key areas are Richmond Center, Broadway/City Hall, Granville, and Waterfront.
The EXPO/Millenium line trains go from Waterfront to a lot of other areas of Vancouver. As a tourist, your key point is Metrotown (In Burnaby), which is a large mall complex, and Stadium/Chinatown, which is the closest to Chinatown.
Seabus goes from Waterfront (Notice a theme here) to the North Shore. Lonsdale Quay is a good spot there, and the trip is worthwhile to get in the harbour.
Almost every skytrain station is also a transit hub. This makes it great to get to a location then hop on a quick bus ride.
Key tourist things and how to get there:
Grouse Mountain / Capilano Suspension bridge: Both are on the North Shore, on the same stretch of Road. 2 options: Take the Seabus from Waterfront to Lonsdale Quay, then the 236 bus. Nice and easy, both Seabus and the 236 is norrmally every 15-30 minutes, and align pretty well. The other option is both run shuttles from just outside Canada Place (Beside Waterfront station) and include it in the cost of admission.
Stanley Park: Hop the #19 bus on Pender St. (between Waterfront and Granville)
Gastown: Steps from Waterfront Skytain Station
Granville Island: Take the #50 on Granville@Georgia st and it drops you off just outside.
Check
https://translink.bc.ca for the transit site, and google maps will do all the heavy lifting for you.
Key crossover points:
-Waterfront: This has all of the downtown rapid transit lines, seabus, and several buses.
-Bridgeport Stn: Crossover point to Airport vs Richmond on Canada Line. Major bus loop for transit to ferries to Vancouver Island
-Granville@Georgia St: all the downtown rapid transit lines, key bus changeover for many directions
-Broadway/City Hall: Canada line (N-S) crossover with 99B rapid bus (Broadway corridor, E-W)
-Commercial/Broadway: End of Millenium line (E-W), crossing with Expo/Millenium line (E-W), end-point of 99B rapid bus (E-W)
-Columbia Station: Split of Expo/Millenium lines
-Lougheed Center: Millennium Line (E-W) / Evergreen line crossover (N-S)
I am a local, feel free to ask me questions. It helps if you can provide specifics about what kinds of things you want to see / ages of the party