I think this is a tad bit OP. A mass Lobotomizer is considerably more powerful than a regular Lobotomizer. Does this affect statuses such as poison and adrenaline?
I think a reason why this won't completely replace Lobotomizerorwhatevermagijie is because of Dimensional Shield. On the other hand, people probably would never use this because of Dimensional Shield. =P
With that, I think that the entire concept should be changed.
Normally when you decide to Lobo something, you'd like to Lobo it immediately. Lobo'ing creatures is a bit different from direct damage CC like Lightning or FireBolt; it can render some creatures completely useless, like Otyugh. Its effect is also instant; it will always happen and doesn't rely on that creature's HP.
If said creature manages to use said skill, and kills one of your vital creatures/destroys your weapon or some permanent, what's the point? The % chance prevents that from not happening. Yet if it was 100% and worked against almost every creature each turn that might be OP. A higher % chance doesn't really cut it either. Lobotomizer is different; it works every turn, but on only one creature.
Lobotomizer is already enough; you won't need to use both a Lobo and a Fence together. Dimensional Shield also offers more DR than Fence. Sure, it lasts for 3 turns, but you can carry up to 6 copies. 18 turns of no damage at all is probably much better than just 1 or 2 DR.