This isn't really JetBrains fault, but the track record of products making full redesigns is bad enough that we do tend to assume that the priorities, values, and considerations of UX professionals run contrary to developers/users priorities, to the point where the result is often less useful/ergonomic than what it replaced.

To be fair, this tendency to prioritize your own values above those of your users is not unique to designers. For example, Linus' insistence that kernel developers "don't break userspace."