We can consider that, but we'd need evidence that two users, when working on the same exact workspace, might reasonably want different behavior. I.e., that such configuration is not just papering over gopls' inability to determine the user's intent with respect to a given package.
In the past we've used configuration when we can't just Do The Right Thing, resulting in configuration bloat and suboptimal behavior in the common zero-config case (I've been guilty of this).
In this case, my sense is that users only want to see lint errors when they're actionable. A lint error in a read-only module is not actionable.
We chatted about this request in a meeting today, and some team members like seeing all diagnostics, even if they aren't actionable. I guess, per my criteria above, this means it probably should be a configuration gated feature (something like diagnoseDependencies).
Given that the current state is preferable for some users and mildly annoying for others, this is unlikely to be prioritized soon.
See also golang/vscode-go#1275. Perhaps the setting should be more fine grained: something like showDiagnostics: openPackages | workspace | all
Where openPackages only shows diagnostics for packages that have open files, workspace shows diagnostics for all workspace packages (+local replaces), and all shows all diagnostics (or rather all workspace + open files in dependencies, like we do now).
Frankly there's a lot of overlap with a more general request we've had to limit the scope of certain features to open packages only, for large monorepos. @heschi has been thinking about this.