The package selection depends on what you select during install.  I think deltarpm isn't installed by a minimal install, but it might be on desktops (I never installed a CentOS desktop, but Fedora Workstation includes deltarpm, while Fedora Cloud doesn't, if I remeber correctly). That's not an issue, though, since deltarpm doesn't bring any functional differences, from a user's perspective: "yum update" produces identical results (and the admin can force yum to not use diff packages via yum.conf - all these variants are officially supported and documented). Both deltarpm and tuned make a lot of sense for a system that only runs as a VM guest, to minimize the impact on the host, and they are transparent to the user. The tuned profiles are the result of optimization work done by RedHat over many months, and fully supported and documented upstream - see the Power Management Guide, for both version 6 and 7.

However, some other things in our Vagrant images *do* bring functional differences. The firewall is disabled, and we add rsync and nfs-utils to the image, since they provide things that Vagrant, or some of its plugins, need. bash-completion is also added on CentOS 7 (not part of @base).  And we create a smaller swap partition than recommended by RedHat's installation guide, to conserve space.

 

The Vagrant images are only intended for Vagrant users, running under one of the supported virtualization solutions. I think it makes sense to adapt them to run as smoothly as possible for their special use case: as a VM guest. But you're right, we need to document any changes, so people know what to expect.