You have some workarounds available to you for getting spammed, and they also need a few more hits before they'll be able to kill you.
You can use a faster weapon yourself to overcome the speed difference, rely on stunning their blocks with a heavy weapon, learn to react as fast as possible after a block, learn to chamber a non-held swing (same timing each time), and more.
Chambering 200wpf spammy longsworder is a suicide, and chambering is a technique that can absolutely not be relied upon.
EDIT: Double posted, sorry.
If they don't hold, a swing can be chambered with the same timing nearly 100% of the time. (only time it doesn't are
very bad/odd angles where they'll glance on you anyways. Stabs on the other hand...