I've not tried Roma Surrectum yet but i've tried lots of other mods including EB and Extended Realism.
What i've found is that you use RomeTW.exe or ALX.exe the AI almost never invades by sea and when it does it's usually a pitiful tiny force. ALX.exe battle AI is a bit better, especially if you use the Darth Battle AI - and ALX.exe will combine part stacks into full stacks before attacking and retrain understrength units to full strength where it can.
If you use BI.exe then the AI will do a few invasions by sea, but mostly of forces that are too small - and it will send in part stacks and understrength units and never retrain them - and its battlefield AI will be terrible.
So whatever you use its disappointing. I'm not criticising EB or Extended Realism here - i like them both - just find the results disappointing when playing as Carthaginians or Romans - no exciting Punic Wars with lots of major naval invasions result.
The only time it worked was in vanilla Rome Total War playing as Carthaginians against three Roman factions, when the Romans did invade aggressively overseas, as they did historically - and did have vast manpower - as they had historically - but then the semi-Biblical out of period Ptolemaic Egyptians would march in through deserts any army would have starved and thirsted to death while crossing and shafted it.
If you play Rome II the battlefield AI is ok, Campaign AI is bizarre, insta-transport armadas make the whole game ridiculous - and half the most important cities in the Mediterranean, including Syracuse, are unwalled hamlets or villages.
Hoping there will eventually be some good mods for Rome II.