It's my honest opinion that a well-placed superiority (not to mention more than 1) can be the decisive force in a game. I will very typically place a 1 command unit against a two command unit and just let them believe they are playing against an idiot. It sounds like a "1 for 1" scenario, but when you gain a planets resources while simultaneously costing them the planet they have now 1) lost the cost of the command-centric unit 2) lost the opportunity cost of the military unit they would have played otherwise, 3) lost the card the would have drawn, 4) and/or lost that last resource they needed to play (insert important event card here).It's undervalued in the meta and I guarantee it will climb in popularity as the game matures.
I agree that Superiority is a good card. Especially since anyone allying with Eldar will use Survivalists. So if your Survivalist at a 2 reward planet is capped by say an Incubus Warrior (which has an in-built deterrent against warlord sniping when it has initiative), you pay 2 rewards to deny 2 rewards to the opponent that he may be relying on for a battle but also gain 4 rewards yourself. So yeah, it's good.
The problem is what to cut. When playing Eldar, you have access to Gift of Isha and Coreworld Gate to compete. Now Gift of Isha is not just a combat trick. Sometimes, due to pinging, the top Eldar is a Guardian, blocking your combat trick option. In the same Incubus situation as above, you can Gift it at a cost of 3 rewards to deny 2 rewards and gain 5 rewards when you Gate the dead Guardian back to hand.
Superiority is a great choice for Eldar allies but for the Eldar themselves, thematically suiting their arrogant isolationist superiority, they have so many great Loyal cards that I find it hard to fit it in.
Of course Starbane alone does not need to fear the sniping deterrent of a lone Incubus Warrior as he eats them for breakfast without initiative. But if shielded, Gift of Isha is really for these skirmisher sniping battles, bringing in a Farseer (draw 1 card them Gate to hand before battle ends) to help finish off an exhausted beefier capping unit. Whilst a top discard Wraithguard and 2 resources saved is such a huge deterrent against the enemy warlord sniping your capped planets. By eschewing the First Planet Snowball strategy (whilst luring commitment via mobility, can't be blanked by Laboratory), you give yourself greater flexibility to snipe as you are not guiding exhausted HQ units, and if you chose wrongly, Foresight (which is best used to win 2 command struggles).
There is a lot of implicit strategy in the build above that I haven't covered. The planet that gives you 3 cards including a search top 3 for 1 is an ideal planet to concede feigning disinterest in deployment then snipe during commitment. The planet that gives 3 bonus rewards if you have less units is an ideal planet to fortress up because you want to deny the opponent this battle ability (as your economy will make you more numerous except against swarm, definitely after a Doom). As it says above, you have to alter the base strategy to suit the terrain and match-up as well as your draws and opponent's strategy. But I contend the base strategy of "give 'em enough rope to hang themselves", the devastating rug-pull that is the last opportunity reset of Pure Control, to come back from the precipice to win, most definitely applies with this build/strategy.
Of course, sometimes, you fly too close to the sun and plummet like Icarus. Whilst exhilarating to snatch victory from defeat, if you can devastate earlier to "gain control", then do it. The build is not necessarily about denying opponent's economy but improving your own and denying him a presence beyond Planet X-1 because once you Doom on turn X, with your entrenched forces (Nullify vs. Exterminatus/Warpstorn) and healthy economy, it's game over.
Well, that's the theory anyway. Now to test it out...