Why does Active Combat System get thrown away and yet Guidlleves get a second chance?

[Renshi]

First case scenario: Fixing Battle System first

Fixing Battle System: New Way to do Older Guildleves.
Enhancing the Guildleve system: New Way to do New Guildleves.


Second case scenario: Enhancing the Guildleve system first:

Enhancing the Guildleve system: Same way to do New Guildleves.
Fixing Battle System: New Way to do Older and Newer (by that time older) Guildleves.

Now guess which one is more effective =)