While some 30+ storey towers would be cool, Vancouver's highrise TOD nodes are driven by a perfect storm of crazy housing prices, severe zoning restrictions that have restricted development and building heights in their actual downtown, and geographic constraints. The fact that Calgary and Denver look so much alike, and have many similarities in built forms and heights, are probably due in part to the many geographic attributes they share. Similarly, Seattle seems to be building crazy dense TOD in Bellevue perhaps due to having the same constraints that are driving heights up in the Vancouver area. In both cases it's ironic that the Canadian cities are smaller than their American cousins and yet exude more of that "big city" vibe IMO.
I think we'll still see some 30+ towers in the suburban TODs, but they'll be the exception rather than the rule. At this point I'd be happy to get quality TOD happening at all, even if it's mostly 6 storey wood frame (which can look good as per University District). More height will come in time.