https://en.subalternosblog.com/post/collegiati-the-gangsters-of-ancient-rome I can think of a couple of units and technologies based on these ideas.

Here is another update to version 1.4.5 for both mods (modiomod-r28 and modiomod-r29). Had Claude check the code and it found a few little glitches and I also improved the info text display for each selected mod  below the list so that it is actually readable. Attached is also the documentation (a readme is also avaialbale within each zip).   Also tried to find a way to display all the mod icons that are available on mod.io, but they cannot be downloaded automatically from within the game. Therefore there is a little add-on python tool that does that outside the game and stores the icons within the  modiomod structure. Not noice but possibly an inspiration for future in game implementation.     modiomod-tools-1.4.5.zip modiomod-r28.zip modiomod-changes.md modiomod-r29.zip TOOLS.txt

Some games with mechanics like the one you're implementing do this. https://www.gamespot.com/articles/e3-06-rise-and-fall-civilizations-at-war-hands-on-single-player-hero-mode-naval-combat-and-the-ancient-world/1100-6147762/    

The only reason they have a range bonus, is when I tested it, it seemed like you had to get really close for the units to actually attack I didn't think about swimming. Maybe if they had like drowning effect, and can't fight, but you can send them to shore, or garrison them on a boat

Are you able to provide ressources? This would underly your advocacy attempt and may lead to faster implementation.