Miasma still does more dmg to an enemy infected with spores. It's also had a range increase modded up its 40+ meters. Miasma now on lower lvl content is almost like the old days of nuke miasma, since it half the hps then does the dot it wipes star chart stuff entirely on its own. They may nerf that they hated it when she used to do that.
I tweaked my build for this most recent change to make miasma last a bit longer since now if they died during miasma duration it automatically spreads even as spores kills them. Also supposedly they're going to add another second to the base of miasma they just forgot to in this recent patch. That and the energy knock down of it is nice. So longer duration combined with lower costs you can keep miasma up on higher lvl content make spores spread on death like before.
It also spreads from the thing you cast spores on the matter how they died so it's good to shoot out a Spore on stuff far away now and then. It's fun in poe doing this cast on Random camp as you run by and they all eventually die when the first guy explodes.
Her current self keeping spores going all the time is easier across the map even larger ones. She is better at infecting the map now than any version since the orginal.
I've played saryn alot in all her changes forms I can take advantage of these most recent changes to dominate a map more than any previous form. You gotta adapt your build and playstyle a bit but the results are nice.