Squirrel,
First of all, you refer to this as a “proposal”. It is not in any way any kind of official proposal or plan. It is an idea put forward for discussion by James Gillespie Primary School, whose concern is improving safety for children going to and from school.
As it is open for discussion, you are free to submit your own views to them.
Secondly, you say it will “disrupt” several roads. Clearly, any scheme like this is going to have a significant effect on vehicle and pedestrian movement, and in that respect it will indeed be disruptive. The question is whether the disruption justifies the benefits.
I haven’t studied the plans in detail, but as first glance it look to me like a very worthwhile improvement to the neighbourhood.
Mike