I find that unless I play very well or have luck on my side I end up losing out to ability stoppers and attack manipulators most of the time. Worst part is that those are the opponents I most frequently counter aside from bonus stoppers, though those are a bit less of an issue. Vortex simply gets wrecked completely by having its abilities stopped, and it doesn't have a great deal of anti-ability cards. C-Blade only goes so far, and Drorb is something I fear would just weigh me down if no stop-ability was in play.
This is the set up I use. I'm considering making alterations of half decking but I'm not sure what changes would be best or what clan would complement vortex nicely. I was considering uppers since attack manipulation would do something in the ways of helping out against other attack manipulator or stop ability based clans.
As for the vortex cards themselves, I'm not sure if I want to exchange Dregn for Oflgn or not. I've experience what a huge life gap can do, and with a proper Oflgn nuke being able to establish a 14 gap I think that'd be hard to overcome.
Any general advice for Vortex?
You need to get T Gaank. His above curve stats will help with the SOA matchup, he protects the damage on Dagg and Deea and of course he crushes All Stars- all great things for Vortex. Otherwise I can't find fault with the characters you use. Cyb Lhia, C Wing and Neloe are liabilities when SOA is heavy but Vortex don't have many better options.
Against Roots or GHEIST you just need to learn to play against them and have a little luck. There is not much that mono Vortex can do against Jeena and Bristone. But if they don't draw their DR, your ability to "fork" on turn 3 should give you enough pill advantage to get the win. You already have C Blade who is the best answer against SOA in general. Izsobahd is a better stop against Roots and GHEIST, but a worse stop against single SOA. If you have trouble with the SOA matchup you might need to change Dregn to a 5* with heavier damage such as C Beast, Sekutor or Shakaarti or use something even more radical like Timber or Ashigaru.
I'm not sure how far you can get with mono Vortex. It's only since T Gaank was released that I've thought of that as viable. All my experience with Vortex is 1/2 decks, where they can be used in 3, 4 or 5 character configurations. Unless Vortex get some more interesting 2* and 3* characters, I don't think their mono is as good as their 1/2.
Yeah you might want to consider half-decking. Vortex fight well when they have an advantage (generally speaking of course), but actually going out there and getting that advantage is difficult unless you had a good draw or got lucky in the opening rounds.
Pairing them with an attack manip clan that has decent damage like the uppers is a good idea, as it gives you leeway in the first two rounds to gain a considerable pill advantage or get a cheap shot in, though it doesn't help much against SOAs (unless dorian is unbanned).
Another approach would be using a low-star vortex half to gain a pill advantage while leaving the heavy-hitting to your other half. Dagg/deea/cyb lhia/C wing is pretty much the standard half deck for this purpose, while clans like gheist and bangers have a bunch of good high-star cards in need of the attack manip dagg and deea provides.