I can't buy this concern with losing time because of some chicanes when on a shared use path.
I expect to defer, and do without exception, to a pedestrian on shared paths, in the same way as I expect motorised vehicles to defer to me when I'm on the roads (not that that deference happens much).
If saving seconds on the commute is all important, I reckon there's some hard-going going on, in which case ... if you're travelling at road speeds, travel on the roads.
I get pissed off at drivers who perform ridiculous manoeuvres, to my endaangerment, for the sake of a pointless few seconds saved. Isn't complaining about the loss of a few seconds displaying the very same mindset as those car drivers?
Regarding the chicane encouraging faster speeds after it's been negotiated? I don't buy that either, not in the slightest. The chicane's been left open a couple of times since installation. I've witnessed a number of cyclists going at 25mph+ through the gap, some whilst freewheeling. Many cyclists will use the lovely smooth tarmac to get a belting speed up.
It's a shared path ... it has to be, because of the narrow western end of it. Why would any cyclist want to intimidate pedestrians, given the sh!t we have to put up with on the roads?