At LVO I was talking to some guys and I heard a cool idea for (if) we get a new battle tome this year. Obviously we would be similar to khorne where we wouldn't have an endless spell per say but what about a really good terrain piece. The terrain piece would be just the bow of an aircraft carrier (or mobile skyport etc) that would have to be on a board edge and can change locations on a die roll etc. It could give buffs, repair ships, bombard nearby units etc but the idea we had been talking about was summoning.
When a KO unit kills a unit, the army gets an aethergold bounty worth half the point value of the unit. You would then use the aethergold to hire (summon) additional KO units. So for example if you kill Archaeon at 700ish points, you would be sitting at 300ish points worth of aethergold to "hire" a gunhauler, maybe some more ark co etc. Just a lot of really cool ideas were being thrown around and made me hopeful for GW doing something great with the update.