> A bunch of plugins have been installed, and lots of manual configuration has been put into jobs so that everybody has what they need to build their software.

Could use something like this if you are using github https://github.com/groupon/DotCi

Job configurations can be version controlled and reviewed like everything else.

Also, the plugin does other optimizations like storing job/build data in a db so jenkins doesn't slow down as you create more builds/jobs. So you don't need "25 Jenkins masters".

For multijob pipelines checkout https://wiki.jenkins-ci.org/display/JENKINS/Pipeline+Plugin