I've noticed there aren't any tides. In the Aegean sea I've reading up (and I don't know if anyone actually lives there and knows who could be reading this) and though the tides are not very extreme, they will experience 1-3 foot lunar tides. Of course depending on the time of year and what not, they would be higher or lower.
It doesn't have to be that extreme. I ran around the whole shore line and the only place that would be affected is by the airport, there's a small port there with docks which are fixed to the wall. They would become submerged so IF you went with this idea you'd have to make those floating docks.
I noticed this because of the storm channel in Agia Marina. To get water to flow up into that channel you'd have to raise the water by 2 meters. Which is unrealistic because of the small tides experienced in the Aegean Sea, unless you went through all the hassle to lower the terrain in that storm channel.
The beaches would all be fine with a 1-3 foot rise. There are a ton of variables and it would be ridiculous to get into all the seasons and lunar cycles of calculating the tides. But for fun and for port towns especially it would add a sense of maybe strategic variation (especially if you've got to consider whether or not the channel has some water in it, etc... but once again the terrain in the storm channel would have to be lowered to allow for 1-3 foot tide to fill it up).
Anyways just a thought about something to add a tiny bit of realism. I'm sure with some tides it would very much effect Altis! I'm sure there are some large and small port towns where tides could affect your strategy in combating in those towns/villages.