It has no lack of features.
You're not lagging behind in any way with the no-subscription repos. In fact, the opposite is true: you're slightly ahead, at the expense of the packages not being as well tested. The order in which Proxmox packages are rolled out is test -> no-sub -> enterprise.
This applies to packages from the Proxmox repositories, i.e., all Proxmox-specific tools and services, the kernel, and ZFS if you use it. For packages that come from the Debian repositories, i.e., the whole rest of the system, everyone receives updates at the same time.