I will be calling this "Saryn revisited 2.0" as 'Saryn 3.0' for ease.
I have been playing with Saryn 3.0 and like her a lot, but I've come up with a few observations:
1. While her abilities work exceptionally well in Onslaught, she does not work as well outside this game mode. Teammate kills (and nukes) break the spore chain more often than they spread it (maximum range Saryn).
2. Her toolkit is not very good on highly mobile missions, only performing best for defense and other room-static gameplay.
3. I do like how interactive spreading the spores is through directed kills, however this leads into the problem in observation 1 with teammates breaking the chain.
4. Saryn does not play well with other Saryns. This is probably for the best to avoid insane game-breaking overpowered squads, but it feels kind of frustrating to compete for kills when you abilities need them to function.
5. I think changing spores' damage to corrosive is a great change, however they feel weaker against shielded enemies (Corpus) without the ability to spread toxin procs.
6. Spore detonation on recast makes large-map play a lot harder, but if it has to stay, i would suggest making it a one-cast action when targeting another enemy (detonate & cast new instance on targeted enemy) to make game play more fluid.
Overall, I would be sad to see current Saryn go if only in favor of Onslaught. There will need to be balance in there, but she is not the only meta warframe for this task. Please do not do any drastic changes based on a few youtube footages taken out of context. Saryn's lethality is largely dependant on map geometry at this point.