Bummer. I thought that I could go with Techpriest assigned to my Plasma Calivers crew... too bad. He could still rain some plasma from a distance or in front of the squad...
I think that both you and Kataklysmic are right about grav-destroyers but still I am not so sure about them. 4+ instead of 3+ is quite a blow, not to mention losing that 6" though 4 grav shots sure sounds nice.
I'll try to experiment a little and have your input written down in case Arc Rifles are not up to the task.
Also look up the War Convocation formation. It's by far the most competitive way to play these factions together, so it's kinda recommended you start your collection in that direction and you can play lots of other formations and detachments along the way.
Nope. Noooope. I would sure as heck try it during tournament but if I jumped at any of my friend with it I would be strangled before I could explain half the things that it gives me. That said I really want an Imperial Knight Warden...
I also think that in 1000 points game removing 1 Plasma Culvering to upgrade Ruststalkers to Infiltrators would be more beneficial than getting rid of few guys. Could even afford Refractor Shield on my Plasma crew. Have a look at those lists then:
1000 points:
1x 10 - Vanguards - 2 Plasma Caliver , Refractor shield
2x 10 - Vanguards - Bare
1x 5 - Infiltrators - Flachette + Tasers
1x 3 - Breachers - Heavy Arc Rifles
2x Dunecrawlers - Eradication Beamer
1x Techpriest - Eradication Ray and Macrostubber
1500 points:
1x 10 - Vanguards - 3 Plasma Caliver, Refractor Shield
3x 10 - Vanguards - Bare
2x 3 - Breachers - Heavy Arc Rifles
4x Dunecrawlers - Eradication Beamer
1x Techpriest - Eradication Ray and Macrostubber
1x 6 - Infiltrators - Flachette + Tasers, Refractor Shield
That would save me the trouble of setting Rangers into good sniping spot. In 1500 points list I could even get grav-destroyers instead of arc rifles if I drop one Infiltrator. What do you think about it now?