I thought folks here might find https://opensource.com/open-organization/17/8/what-to-do-when-nobody-participates interesting as well as the “open organization” project in the article. It covers handling criticism and lack of feedback in the design process.
That is a very helpful story. I would interpret the problem as one of managing uncertainty: If the ideas are provided in an abstract and still-possibly-changing way, people have a hard time imagining themselves using it and/or don’t want to invest time a moving target.
On the other hand, if the uncertainty is reduced, graspable examples are provided, and there is one set-for-now thing, people are likely to feel left out of the loop.
One way to deal with it could be workshops to reduce the uncertainty of “someone might change it without me knowing” and to get a natural exchange of different viewpoint within the organization (what feels not-so-good for some might be an essential thing for others, and better they have the conversation themselves then obscured via the design).
The latter is not even directly part of design, but since designers often deal with wicked, multi-stakeholder problems, it can be essential to allow people to exchange seemingly about the design, but in the end mainly about their priorities and needs.