The reasons it changed were:
- We were close to running out of letters and some of the letters that we were forced to use made absolutely no sense.
- This way allows for expanded functionality where each ability can have parameters.
Example using summon doing something that wasn't possible before:
This tells the npc that it has special attack summon target to itself on a 1000ms(1 sec) cd so long as it's hp <= 100%.
Alternatively you could do:
This tells the npc that it has special attack summon itself to its target on a 6000ms(6 sec) cd so long as it's hp <= 97%.
Such things had to be hard coded before but now we can set them up so they don't have to be if we so wish.