It has been quite some time the new critical system has been implemented. Hence, my memory of the older one is a bit tainted, nevertheless, I will attempt to recall all that I can remember.
The old critical system made heavy use of the raw number you saw on your stat. It didn't convert them to percentage figures like what occurs now.
The higher the number, the higher your chances of both gaining and landing a critical.
Usually this number mechanic made it easier for one to gain criticals.
Landing them differs than how it occurs now; which leads me into the blocking aspect.
Similarly to criticals, blocking made heavy use of numbers as well without incorporating percentage figures. If your block was higher than the opponent's critical rating, chances are that you would block the hit incoming.
Blocking also worked on a mechanic that if the first opponent/player blocked a hit, there's a high chance that the rest of the team will also block the hit.
Nowadays, Critical Decay has made it harder to gain criticals and even harder to block them.
There was no such thing as "Critical Decay" within the past or during the first rollout of the Critical System.
