It might sound a bit unorthodox, but really, isn't there a way to solve this properly (from the point of view of Jenkins users), without messy and inconvenient workarounds?

For example, if a pipeline is saved (on the UI or with CLI or ...), it might be parsed automagically and look for parameters only and do the same with them as if the job was run? Or actually run the job on save but somehow limited to parameter properties only (and hide the run from the history)? Or...

I'm sure it is not very simple to implement but it is quite a Major issue...

it might be parsed automagically and look for parameters only

That is exactly what this issue proposes (for Declarative Pipeline).

I guess there is no real chances this gets implemented since it's been more than 3 years since it's open?
Is there any good way around this without failing the first build but also having to run it manually?

mcosta : From felipecassiors's comment above (slightly simplified), we add this to pipelines:

stage('prepare') {
  steps {
    // Initialize params as envvars, workaround for bug https://issues.jenkins-ci.org/browse/JENKINS-41929
    script { params.each { k, v -> env[k] = v } }
  }
}

qnerden slightly? This is much cleaner and better! Thanks a lot for sharing.

One important thing to note is that none of the parameters should be included in `environment` section of the pipeline, otherwise changes made during a stage (like this 'prepare' one) won't be retained for all stages.