When Serum finally has all the features a subtractive/wavetable synth has ever had, and of course some original ones, and you feel your work is done, I would throw my money at you for an additive synth.
I haven't seen anyone do it well except Image Line. I bought Loom this week without trying it, like a moron, because it's on a ridiculous sale at a reseller (don't know if I'm allowed to say the name. I'm not advertising obv,) and just found myself so profoundly disappointed with the modulation options and overall level of control. At which point I thought, dammit Steve Duda should've made this.
Ever thought about it?