Debian only "does too much" if what you want from an OS is a simple platform on which to build your own bespoke solution. The BSD operating systems, and OpenBSD in particular, abdicate a lot more responsibility for actual system management and application deployment to the sysadmin, while Debian provides opinionated defaults (in the form of package install layouts and configuration styles) that work for most environments.

Both have their place, but for general-purpose servers, I find Debian to be a much more productive system on top of which to build solutions. For firewalls, embedded storage devices, or load balancers, on the other hand, I still reach for a recent OpenBSD install disk, because the smaller footprint and security hardening have real advantages for systems running such a limited set of services.