better translation or simplification of GF(a & Fb)
G(F(a & Fb))
is equivalent to G(Fa & Fb)
, yet I know of no translator that is able to translate the first as efficiently as the second.
It gets worse with G(F(a & F(b & Fc)))
etc.
Look at the rewriting rules in the LIO2ALBA paper.
It has GF(a & Fb) = GFa & GFb
as well as GF(a | Gb) = GFa | FGb
(to apply in the other direction).