Via is going to be a huge liability while Tachyon is played. If you want a stall game Via is incredible, but that is hard to pull off. Wraith+Vis+Legacy/Beacon is great to catch a team off guard, but it lacks staying power for multiple rounds and requires a map favorable to Wraith sniping.
If you can afford intercept-danger sense vs the opponent this stall is epic, otherwise it is just good, which means you still need a map and opponent you can play a stall game with.
Mostly Vis is a hero you would need to last pick when they can't counter pick you and you know all the variables of the match. That means you need a good duo strategy with a counter pick third hero design that can rock visionary.
Visionary also works better against melee characters than ranged. For one, if she gets away from Decoy Projection then when she swaps, the melee people have to chase her down. For another, they have to be in Twist the Ether range to hit her. I found her very good vs. Proletariat whether she goes Twist the Ether and Foresight or Decoy Projection and Foresight. Any attacks with only 3 or 4 dice she can mostly survive with little to no damage. Any more than that and she can be in big trouble.
As for Wrest the Mind being costly,losing one health to re-roll a very strong attack or very weak defense can save the team from an incapacitation.
Against tachyon- since Brain burn happens before the visionary is incapped, There is all sorts of potential for the visionary to win a game by being taken down. If the game is tied, taking down the Visionary could be the worst possible move- especially for someone who tends to use her HP for fuel like Tach!
in addition, Foresight can be used on things like movement rolls... Which can royally screw up Tachyons plans.
Since Wrest the Mind can be used multiple times, you could wait for your ally to finish their turn whomping the enemy and making them exhaust thselves to keep a few HP.. And then Wrest the mind on your buddies movement roll (as many times as you need) if you think a brain burn could take out the wounded foe.
Its not something you'll use every time- and like all the characters, you can get countered, run into unexpected tactics, or have a team that doesn't click. But she's not a one-trick pony or last resort, and she can be the lynchpin of a very nasty team.
During the times I do play with Visionary, I favor AIMing over taking a DODGE because I want that threat of Brain Burn (IDK if thats a correct play, but it's what I've leaned towards). Tack on a token generator like Legacy and possibly Dawn with Hammer/Anvil or Blood/Sweat/Tears (an offensive minded Citizen for sure), you could do some real damage and may not mind not running Decoy Projection while still keeping Visionary up front supporting with Twist and Foresight. +ATK tokens and Maelstrom could be a game ender.
You also gotta figure she needs to support an already strong duo. And I've said it a lot during playtesting that Legacy/Dawn are so good together that you could plug anyone in that 3rd slot as a "tech" option for a counter-pick. Visionary could easily fit right in there.
I'd love to hear some more details about this Peter if you could manage. What were common groupings that had Visionary in them? What were common power loadouts? Did she prove effective in the matches she was in?
I can't speak for RevoCorp, but at our first Indianapolis Tactics Leavue gathering featured two appearances by Visionary. The player who used Visionary paired her with a defense focused Legacy and won both matches.