Now hear this:
best way to make the game harder and thus more interesting is by doing completely opposing thing to what you suppose to do. i will explain myself:
lets say you play as Julii - dont expand north!!!!
instead try to expand east to dacia and macedonia/greece where brutii will naturally expand.
i got very interesting results with this - gauls destroyed senate army and engaged in war with brutii, i lost all my provinces in italy but gained reach former greek and macedonian provinces.
for now 2 other roman factions struggling hard with very powerfull gauls - hehe i totally interrupted their usual expansion pattern so cleverly
the AI just dont get from where all those gauls came rolling all over them...
BTW i am playing on VH/H.