I'm not sure the problem is as dire as you make it sound (or that there even is a single practice by Wiktionary admins), but I'll assume it is for the sake of argument:
Brian McNeil wrote:
Block with no warning is - in most cases - unacceptable
This is not a universal rule. It's a simple point to make, but you seem to be taking the opposite to be true as an assumption.
I'm sure some might argue this should have been raised on the wiktionary mailing list, but I believe if a project has - as in this case - earned a reputation for capriciously wielding the banhammer it needs the wider Wikimedia community to say this is unacceptable.
I don't think it does. A foundation-l thread started by a community outsider nicely misses all the shared community norms and consensus that have developed over the years, as well as familiarity with the actual circumstances of the project (like having what I would say is one of the highest article-to-recent-changes-patrollers ratios to be found). The problem here isn't just that none of the English Wiktionary admins has been informed that "the wider Wikimedia community" views their practices as unacceptable, but that it is a fact for any community, whether it's Wiktionary, Wikipedia or Wikinews that you have no chance of change unless you are actually making your arguments to the people you disagree with. I recommend you actually engage in discussion with Wiktionary editors and, say, present *reasons* for why you disagree with their practices. After all, I'm sure that Wiktionarians have their own reasons for doing what they do. :-)
Dominic