Windform totally works, I leveled one to 140 this season.
Here some gear combos:
note that it isn't very fast because it was still under construction and just to show items. I also hang around on screen to show procs, where in reality those monsters are poisoned for 10+ seconds, and they would otherwise die offscreen If I left them (snake duration is extended by whirlwind duration, amatoxin, additonal poison item, gladiators dominance bonus).
Whirlwind works well with snake stance, because you get 150% wdm mod to snake stance (+ww added poison damage by itself) and then that is multiplied by spell damage to direct hits. So you get snake stance damage via AOE or other attack procs, and then much higher poison dps to enemies you hit directly.
It can deal competitive endgame damage, managed to 2-shot astrogha with it, beat many endgame bosses.
It isn't as strong as snake bite, lets get it out of the way.. but its very likely gonna get nerfed. Windform single target also takes much more investment because you need spell damage gear, where for snake bite you don't (because it doesn't do anything and skill is tuned for dealing super high damage without it).
If you just use simple setup with crafted crystal sword, then you can already do really fast duncraig clears, since monsters are mostly melee there, clumped together, they walk into your aoe damage and get 1-shot by it. Quite comfortable runs really and fast.
Ubers with monstrers spread around lack aoe, and you need to search for other higher range procs, such as timewave (or straight up spam couple of time waves by yourself in between whirlwind). It will add bonus poison damage from windform while you use it as well as its life on striking.
As for dual wielding for this.
Advantage is: you increase hit rate of whirlwind (thus proc rate) by x2, it hits twice as often.
Downside: you lose block (huge), movement speed from glad dominance, and poison duration bonus, which is very important.
In other words, for this particular version based on poison, I don't think dual wielding is worth it.