One thing about the original RTW Vanilla which makes me think improve (I haven't figured out the original EB Marian Reforms yet) is the Marian Reforms.

The Roman Republic needed a crisis before the Marian Reforms were possible, what was neccessary were crushing defeats at the hands of the invading Germanic tribes, a Numidian Kingdom and Army operating with a high degree of success by surviving, the levy of the propertied classes being stretched to the limits.

However in the original RTW Marian Reforms happen when you become wealthy, in other words when you become completely unstoppable you get the Marian reforms, you wouldn't think the Republic was stretched to the limits and not in an entirely winning position from the game mechanics.

So I propose instead of the founding of the greatest proffessional army before gunpowder being triggered by you already being unstoppable you get the Marian Reforms if you are losing land, losing battles, and at war with three or more people, and outnumbered on one or two fronts.

That way the Marian Reforms are a challenge, just as they were for Marius and the republic, instead of just being a reward for overwhelming victory.