Blog Post
But why did anyone R9 SA when a chimera with R3 Iden can take out a full R9 Levi line up? Those who R9 all pilots like this are not particularly efficient with resources. So I am unsympathetic if they suddenly feel the need to R9 Tie dagger now.
You ask "why did anyone R9 SA?" - let me give you the actual answer from someone who has got Lev (and I worked (not paid) hard to get it as soon after it came out as I could to maintain my fleet arena income).
The answer is this : 99% of my fleet arena battles are Lev mirror matches and having Sith Fighter in the starting lineup is by far the most effective so a R9 SA is a good investment for this. Granted, it's not useful elsewhere which is why removing it's usefulness here hurts for those who have invested earned resources in it).
I see a Chimera maybe once every couple of months if that but someone always knocks it back very quickly - it may be a useful counter elsewhere but obviously not fleet arena.