I dont play this mod so its hard for me to comment but i have done alot of work with AI and it seems what you want may be hard to achieve well without changing your playing style the nature of the beast is you can make the Ai very defensive and this boredom you speak of will happen or you can make it aggresive and this ganging up you speak of will happen . why will ganging up happen on a aggresive Ai well one of the factors the Ai looks at when deciding to attack is your list of alies and enemies so if you have made few friends and many enemies you are weak to attack so it goes to war against you
If you go for an agresive Ai you can avoid this ganging up by one doing alot of diplomacy with the other factions offering them gifts of map info etc to keep there relations with you high when and if you attack nations send a diplomat first and ask for something they wont give with the demand of accept or we attack so your global standing doesnt drop when you do . play smart lure your first victim to attack you till he is excomed so then you will not only not be penalised for attacking him you standing with other catholics will actually go up or attack non catholics such as the muslims pagens orthodox and sun worshippers
An agresive Ai is the most fun to play but it requires thought and planning if you expect to just willy nilly conqueor and have the other factions sit back and go meh let him have what he wants your kidding yourself thats realistic the world let hitler take poland but when his eye turned even further did they sit back and go ah let him have it NO it became world war
If you play like a tyrant to conqueor (and getting enough regions means you do if you try to do it quickly ) then they will gang up on you .
So i dont think its agressive AI thats the problem more that you play ill to agressive AI but then also find it to boring when the Ai is defensive try an agresive AI buit adapt some of the ideas i have given there are many more such as marry your daughters in an aliance to surrounding factions to buy peace from them when you go to war elsewhere etc
Play smarter or you will be a victim of your own conquest . I am not a fan of slower defensive AIs as they allow you to much freedom to take what you want and steam roll the world so really decide how you wish to play