The landscaping requirements typically stem from multi-residential districts and the age old idea that you don't want a giant building on a parcel without some sort of green space (for recreation, beauty and so you have some permeable surfaces rather than nothing but concrete). The problem with this idea in many of the urban mixed use areas is that it doesn't always work. I've said this before and it comes from writing zoning bylaws - zoning or land use control paints every parcel with the same 'broad brush'. So a zoning bylaw assumes every parcel that's R-1 is the same (typically a rectangle with at least 30' wide frontage and flat). That's why you get into the need for variances (we call them relaxations out here in Calgary). These are not bad things - because we have to understand the circumstances are different on each parcel.
One of the things that we have been trying is with some of our mixed use/transit oriented areas out here in Calgary is landscaping at or above grade. The problem is that the percentages still favor landscaping at grade versus above, to create a pleasant interface. I don't always agree with that, specially when you have active edges like storefronts or townhouses.
I'm working on a project right now called
Bridgeland Crossings which is in the Bridgeland Transit Oriented Development Area here in Calgary (I'm the planner doing the permit). It's had 2 different rezonings on it and was previously approved - but the permit lapsed, so we are in the process of re-approving it. Problem is that the landscaping requirements are one of the big deficiencies because someone had the 'bright idea' to put into the site specific zoning a provision for landscaping at or within 1m of grade. Well, most of their landscaping is actually above the parkade which puts it greater than 1m from grade on the second level in the centre
(you can see it here) - so that's created a huge list of deficiencies.
I don't think people need to rush for pitchforks when the idea of a variance (or relaxation comes up) - planners just need to approach it better. I always see it as an opportunity for negotiation. If a developer wants a relaxation for say height (if it's not governed by something like a viewplane or a 'non relaxable height limit') then - what do I get for the City? You want height - I want more trees, or a better design of the facade and interface with the street. It's all about how you approach it - facilitation versus confrontation.