I thought system hack would be really popular but it seems not ;p
There is only one spot open on ECM.
After energy drain, hull repair, and inhibitor beam.
Ion drops EMP so it is hard to say no to it. I do, but I can see it being difficult for other players.
I prefer hull repair + ion inhibitor + stasis as basics… That leave one spot for the 3 other modules available. Hack is really fun on storm viking 
But the weapon system inhibtor is also great to help protect an ingi. I prefer energy drain on waki AE too.
So I guess that’s why we don’t see much.
It’s also less “flashy” than the holoships spam
Also the Hack module is T4 and T5.
(Timebomb) Holoships are T3, T4 and T5.