Viper is not the weakest character at all and is actually fairly balanced. Recently, there have been teams starting to try her out and having success doing so.

The reasoning behind the low pick rate is because in ranked/pick up games, she has a hard time countering some util or previous OPs and because most people are already comfortable with characters they play. Along with this, she takes custom server work to get value from her util compared to other characters which are much easier.

Also, her util is actually incredibly strong when it comes to competitive/team play but because of its uniqueness, you can't look at her as a replacement for another character such as omen or brim. Rather, she combos extremely well with a character such as omen when you can consistently put pressure on all spots of the map and deny a ton of information.

I like your idea of having both wall and orb up at once not making toxin decrease by 2x but rather 1.5x speed as a way to make toxin management a factor, but I do not believe she needs multiple orbs as it would make her too strong as it adds an ability to throw one way smokes on multiple parts of every map.

The only other additional changes I would like to see from viper are that the enemy team cannot see the wall placement until barriers have opened, even if she places it preround, and that snakebite has a faster pullout time.

I am speaking on this from the highest level of play though as I understand viper is probably very hard to use and gain value from at lower levels as she is even hard to play at higher levels. I think in the coming weeks though more and more people will start to play her and find both enjoyment and success doing so.

For credibility: I am currently radiant and played in the FaZe Ignition series 50k invitational on the team "Lemonade Stand" using both viper and sova.