The problem is not with this site in isolation. The problem is with the entire neighborhood. 40 m of separation is going to hugely constrain what is buildable here.
Fair, to a point, if the City is seeking this throughout the district.
Though....in general its important to remember (as I encourage City planning to do) the goals of thinks like separation distance or floor plate size limits, or the angular plane are about a means to an end.
Greater sky view, acceptable privacy, less shadowing (or greater access to sun), and the aesthetic consideration of not making making monolithic fortresses.
These all work together...........as example.....at greater height, greater separation becomes desirable, both visually and because the greater height results in longer shadows.
An angular plane, while overly crude and cumbersome when enforced thoughtlessly aims to address the same issue, and in a way so do restrictions on floor plate size.
One must examine the interplay of these. The measurable, objective effects and perceived, subjective ones., when taken together.
I won't get into how that works out here across the larger area, because I would need to go back and look at the current assumptions, in both the district plan and specific applications in process.
Doubtless I would disagree with some of the choices made.........but that's just too involved to put on this application for now.
In this particular case, I don't think pushing the towers on this block closer together does anything inherently useful. It doesn't really result in room for another tower. We could look at the i site as high mid-rise instead, with vastly different assumptions modeled out...... ( I might well prefer this) but I simply don't think we can say 40M has an obvious negative consequence here, unless you're linking that to aspects of the height for the form you don't like, that might evolve differently with a lesser separation.