Is the astro banner a much include in a starborne army? do folks do fine without it? seems like a lot of points for a little bit of casting bonus... mostly seems like a D3 conjure generator, but for 140 points that seems like a lot?
That's not really all for 140 pts. 1) You get 1D3 CCP - Pretty reasonable 2) Every caster gets +1 to cast if within 12" - Really good all around, especially if you have multiple casters like Skink Starpriest etc. 3) Every caster gets 6" added range to their spells if within 12" (except Endless Spells) - Extremely good. This coupled with Balewind gives Kroak a 22" threat range with Celestial Deliverance instead of his base 10" range. It is pretty big and noticable difference on other casters too. 4) Every model wholly within 12" gets a 6+ ward save - It is pretty alright as it gives some protection against MWs, something none of our models have. Every bonus is really good and you dont even have to roll a dice - It is just a passive buff aura as long as the Astrolith is alive. It is a must-include for me.
If you aren't going all out on summoning you can make it your general in fangs of sotek and give it the old and grizzled trait. Extra command points are always handy in that constellation.
my current list plan is to use summoning to bring in a salamander team unless I really need a skink screen. nothing above 10 conjure points on the chart. With a slann as general I get D3 + D3 more if I reduce spells, so I guess it depends if I want the additional d3 astro points.
I nearly always take the Suarus Astrolith Bearer in any list that brings Kroak. The extra 6" to spell range and +1 to casting are huge. That alone is worth the 140MPP. The D3 CCP is just bonus.