It is not hard but it is time consuming. The only event that goes over 16 monsters in the enemy team is the super challenge battle.
Try use an unwanted friend monster against them - they will not life flip those, it’s because the General AI and the AI in that battle are not linked which leads me to believe there is a general set of parameters on the top level that are hardcoded. Meaning if you changed it you will change them on all levels.
There must also be one for team cost - recall the time they fucked up and took very long to recover?
This means that if they want to increase team size to 30 they will have to more than likely setup a separate AI for it and redo all the parameters - this is as you say not hard but it is time consuming,
I believe they have 4 or 5 full time developers on this game which is a relatively small team and for whatever they are planning on the 1 year anniversary it must be big so unless they are creating it already Theres a phenomenally small chance they will start working on anything else then what they are doing right now.
JOIN THE DARK SIDE OF THE PLAYER BASE MWUHAAHHAGHA. No seriously don’t worry they wouldn’t lol