Oh man, I could write an essay, but I shall stick to those things that I found RTW in general lacking, and that would make EB even more top tier.

1 - More complex Rebel faction system. In RTW and EB the rebels were a single faction with generally one hivemind. EB attempted to give the feel that they were independent city states with the scripted events that control the Lusitanni-Celtiberian alliance or the Sinope/Crimean-KH alliance and that did help a bit. If it was possible at all to take it further and give independent city states (or at least the ones of import) some scripted behaviours that make them act more independent and even allow them to be individually allied to certain factions, then that would be a great way to add to the depth of the game.

2 - Hiring units based on your alliances. Instead of having to rely on naturally replenishing mercenaries, if your alliances could generate a separate pool of soldiers that could be hired that would be cool. I would only want this if it were realistic. EX - an alliance with the averni could grant the romans a modest supply of lower tier celtic units and a small amount of elites (with marked-up mercenary price). Since the Romans had a tendency to equip their celts in a superior manner to the celts themselves, maybe the units could be inherent to each factions techtree, but one requirement could be an alliance with a faction of a certain culture. The only difference between this and capturing an allied state is that you would not need to go to war and take another factions territory with a specific culture - as was the case when I had to invade parts of gaul to get helvetti units and neitos.

3 - Less bloodthirsty AI. I thought that aside from the inevitable "Territorial Expansion" penalty in ETW, the Empire political engine was pretty solid, I could actually have an ally who participated in battles and who didn't backstab me the second he was close enough to see me.

4 - Better AI tendency towards naval invasons. As KH and Casse I was nigh-unkillable because no one ever came to Rhodes or Krete, or Britain

5 - I don't know if this is more or less historical, but I don't particularly like the patron god temples with specific traits. I think every faction should have a generic temple line that improves certain things based on the religion as a whole, rather than specific deities. In RTW it was stupid what sorts of things came from a certain temple (weapon upgrades for example), and in EB you find that in some cases one temple is completely better than the other - they can both add the same happiness bonus, but then one has an extra law bonus of up to 20%, or more trade income. We also know that the morale bonus is largely worthless. I would rather have either a single temple line for each faction (bonuses should vary between factions), or allow each level of temple to be converted the same level temple of a different God, with maybe 1 turn per conversion, since building a temple up from the ground is annoying when you just want to get a different statue inside.

I'll be back to harass you all with more soon, but I have a Mol Bio test :S