AS 690 has about as complex a set of policies as anyone I can imagine.
RIPE-181 can handle our import policy just fine. We've suggested some
minor syntax changes that would substantially reduce the number of
lines required to express this (without defining a few thousand macros
to accomplish this), but the current syntax does provide the needed
flexibility. Our export policy cannot be expressed in RIPE-181
because some of our export policy is AS path based. An AS path
extension has already been proposed (or at least batted around on the
rps mailing list).
Limited AS path expressions (policy with respect to your neighbors) has
been coded and deployed, though not yet announced or generally documented.
(Let me know if you're interested in using it). General AS path
expressions are in the works.