We would like to have one solution packages.config rather than individual packages.config at the project level. We have a rather large solution (over 300 projects) and we have had issues with project config like people forgetting to upgrade all projects to a specific version of a package. We realize that it will lock us to a single version of each package across all projects and we are ok with that. I've attempted do this to a few projects by deleting all packages in the project and then trying to re-add them through the solution rather than the project but its just re-adding the package.config at the project level. I even tried to manually delete the project level packages.config file and add them to the solution level and then using the solution level "manage nuget packages" dialog but the same thing happened.
I'm kind of going off this post which is quite old:
Manage packages at the solution level