Well with RS 1.6 you do get all of what you asked and a lot more than you might think. the new terrain in RS 1.6 is probably the best of all mods(RS2 will be miles better). The map is huge so you'll have to fight more field battles unlike most mods i have played so there's little constant siege battles. 35 different named legions,many unique hoplites like syacuseian hoplites etc. prob the biggest diffence between RS 1.6 and RTR is Historical accuracy which RTR is better at. AI depeneds on your exe RTW->BI->ALEX i resently got alex and with the new terrain im having the most challenging campaigns that ive ever had playing any mod. And also RS 1.6 is ment to be played on hard/hard or hard/Very hard so it will be a challange. And here are some pics for your you. These are from my up coming Post empires Update.
A section of greece
And a action pic
u can also click the link in my sig to look at my RS1.6 slide show which has other battle pics of Germans more Macedonian s and Romans