This is not exactly true. Servers are not uniform. While low end units use similar hardware to desktops there are ones with radically different hardware that makes the desktop compatible units look like tinker toys. POWER, SPARC, PA-RISC, CELL, you find archetectures here that are completely incompatible with each other.
Since most of those are being desupported by just about every major vendor, they're the ones that look like tinker toys.
PA-RISC has been dead for years. It was slated to be replaced by Itanium (with HP being the only vendor still using
that even), but that's more or less dead in the water due Oracle's announcement that they're pulling Itanium support for all their software. There's a few die-hards still using it, mostly in the US Government, but eventually those systems will be replaced.
SPARC is floundering, despite Oracle being desperate to justify their purchase of Sun and pushing it hard. It's clear they're losing the war to cheaper systems that can be clustered to provide greater performance and comparable reliability.
POWER is probably the only of those still seeing serious development, but you won't find those outside of an extremely high-end OLTP setup in a bank's mainframe, or in Cell/Xenon CPUs on consoles. Even Apple, once the champion of the architecture, has abandoned it.
I'm in the process of migrating a large financial system off PA-RISC onto x86-64 for my day job. Each of our database cluster nodes has 32 cores and 512GB of RAM, hardly what you'd call low-end.
It's
possible that B&S or other games use a different architecture for their server farm, but given how commoditized the server market has become, a developer would be foolish to design such a system.
Also, since we have it on pretty good authority that the COH servers are virtualized, they could very likely share the same hardware with Blade & Soul without an issue. The only question is that of available CPU/memory resources, and IOPS on their storage units.