A few parts of the Halifax waterfront have the activity levels and scale of Granville Island, but with nicer buildings and a nicer boardwalk. The seawall doesn't actually go around Granville Island, and I disagree with earlier comments about the interestingness of the nearby large footprint, single use 1970's-era co-op housing.
Vancouver gets more cruise ship passengers (840,000 vs. 290,000 in Halifax) but they mostly (all?) converge on the Canada Place area and as you said that stretch plus Coal Harbour has little going on at the waterfront level, although there are some crowds and there is the odd restaurant. Most of the downtown Vancouver peninsula seawall is parks or just the boardwalk with a restaurant every so often and lots of residential buildings in behind, with major commercial activity set back several blocks from the water.
Nobody is going to believe me but the crowds along the waterfront in Halifax is similar to what you see in Vancouver (which is moderate; the Vancouver seawall generally isn't packed in with tons of people even on nice days). The picture below is what I've encountered on a typical nice summer day, not just when the stars align.
The biggest assets Halifax has that put it in the same range as Vancouver are its historic waterfront buildings. The seaport area piers were built around 100 years ago and they are about half a kilometre long. The cruise ship terminal is there along with Pier 21 and a bunch of other stuff.
There's nothing at all in Vancouver like the 200 year old waterfront warehouse buildings in Halifax. I'm not sure what it's like today but the Keith's brewery market used to be a rabbit warren of old stone archways and cellars full of vendors and businesses. There is nothing like that in Vancouver.
Like I said the WDCL in Halifax also seems to do a better job of event programming and adding in little vendors booths, things to see, buskers, etc. The Halifax waterfront probably has more public art and more of it ties in with local and regional history. For example there's a marble lion statue donated by Venice commemorating John Cabot, an Acadian deportation monument, a Samuel Cunard monument, a merchant marine monument, etc.
There are aspects of the Vancouver waterfront experience that are better too. The beaches are nicer and more numerous, the natural scenery is nicer, and the modern architecture is better on average, for example.
None of this follows directly from tourism stats and you're not going to see an abstract data-driven proof of it anywhere. It's just my opinion.