I recently installed EB Alexander hoping there would be more naval invasions. However I didn't see things really change comparing to vanilla EB. I decided that was maybe because of VERY expensive ships? In my first campaign for Romans after 10 or so years playing I noticed that Polemaioi was the only faction who use naval fleet.
So, I left Roman campaign for some time and started as Qart-Hadasht. Before that I'd slashed the upkeep cost for every EB ship type twice. Even now, only factions holding 10+ provinces could deploy ships and support a strong army. I thought that would do but there is stil not much activity on seas except for pirates...
Bookmarks