Whether or not lore wise they would drown, I think it works better mechanically if they do, so you can't just hide at the bottom of a river for hours, or simply because it would help say, not allow players to walk way off map along the presumable sea floor. The continents are assuredly bordered by an ocean.
Definitely no need to waste dev time and effort on implementing swimming animations and mechanics, but I think having bodies of water to give visual variety and make for tactical terrain, it would be really cool. I wouldn't want water to have crazy tech movement, and as far as gameplay is involved I would only want it to cause movement impairment. Not a big deal if it doesn't make it, but it could be really cool.
Well they could replace the water with some kind of high intensity acid leaking out of a coastal facility or just have a crevasse full of lit promethium creating a fire like lake. Ice could be used to allow infantry across but disallow vehicles or it would break making the bridge a strategic target.
..What kind of heretical name is "Bob" ? But, on-topic, I think the impassable-water sounds good, also for the visual variety as mentioned, and to avoid any gameplay/mechanic problems. Whether it's then lorewise a Rule of Engagement or it's because it's acid from a facility nearby, or some other pollution, well, mostly anything works there.
I just quoted it for a Reply. So we are on the same "side" on that, i just say, that somewere (if there is water), it needs to be deep water as well.
I have an imaginary friend called "Bob the Ultramarine". I will not have anyone make fun of him! ...other than myself.
