I'm not 100% on board with this but I do like the concept. I think the Negation catalyst would be too powerful (imagine carefully crafting your Boss Node only to have someone come in and render the catalysts you've invested in useless). However, I think giving the player a slight edge is nice. Normally my philosophy is that defense should get more help since Player > AI, but adding restrictions (like "Must Use X Characters", lower FS, etc) could keep it balanced. Although, if this was implemented, I would hope the devs would create a separate Offense catalyst. I'd hate to broaden the pool of potential catalyst pulls too much further.