Decred and SIA ASICs are around the corner, not sure if its worth to develop dual mining for those algorithms
We'll see how fast they will ramp up production. Given the past history it would take some time before the GPU mining for these coins becomes obsolete.
I'd like to see Sia added to new version of dual miner
So one vote for decred and one for sia so far. At any rate, decr and sia will be the first two supported secondary coins for dual mining, probably in this order,