As someone who works for Calgary Transit and has driven LRVs, in my opinion I think there's a few problems with the O-Train, many of which will work themselves out. The biggest is just unfamiliarity of both Transit workers AND customers; once people learn how the doors work, it becomes less of a problem. LRT is new to Ottawa, so it takes time to adjust. People in many of the other cities you've listed have had LRVs for decades - even if new models of LRVs arrive, operation isn't typically that different from one model to the next, and the customers and employees are used to the system. Of course we have door problems, but we're just used to dealing with them.
There's a few other issues that hopefully OC Transpo will learn quickly and adjust (some they've already said they're changing) - when you have a problem LRV door on the main line, you can't take time to fix it; just turn it off and lock it closed. Trying to get it working will take way too long and will destroy your service (especially when people are unfamiliar with them).
John Manconi also said that the doors are designed to fail open after 3 failed attempts to close, which is way too few. Here in Calgary, we found it was causing too many problems after failing open after 6 attempts, so we changed it to 30. When it's busy, people and their stuff are always getting in the way, so if the door fails open after only three attempts, you're constantly going to be dealing with doors failed open.
I believe they also mentioned that the doors have a safety eye/beam to detect obstructions, which can also cause delays. In all but our oldest trains, as soon as the doors are deactivated (our doors open with push buttons), the safety beam deactivates. This prevents people's feet, bags, strollers, etc. from accidentally blocking the door (unintentionally or on purpose) - the sensitive edge is still active to detect any obstruction.
While many are understandably upset and bashing LRT for the rocky start, I believe it will be a great system for Ottawa in the future. My two cents anyway.