you'll need to get 1 more guardian for that unit so she can have a better scoring unit. always aim for even numbers so she can maintain her scoring status for as long a possible.
also, i'd swap that power toy/shimmer shield to the twin shuricats when taking bladestorm. one neat little trick i've been trying to develop is to use an 8-avenger bladestorm squad supported by a 10 avenger basic squad. this way, you can lose off a bladestorm, then use the other 10-man unit to cover the now vulnerable 8-man squad.
if you do give an avenger squad defend, i'd go for the diresword option as it
s great fun against multi-wound opponent's!
(and you'd be surprised just how many of 'em there really are!)
the next things to look at;
anti-tank:
6x fire dragons inclu exarch w/dragon's breath flamer. mount them in a wave serpent w/shuri-cannon & twin-linked shuri-cannon. nice little unit which can also see off large crowds!
anti-meq:
5x dark reapers. exarch not really needed, but if you do go for it, i'd honestly try to magnatise the exarch because it really is a toss-up between the eldar missile launcher or the extremely tasty tempest launcher!
vehicle:
war walkers. god how i love 'scouts'! plus, these guys throw out so much fire power it really will turn opponent's white!
cheers!