[Kipper]

I haven't read through the whole thread but for my 2p worth, I wouldn't redefine the game to have giant behemoth movable ships with 40 crew slots etc. There's no need for it imo.

For me, to add naval combat to planetside you just need tanks that have boat hulls instead of wheels - they still require 1, 2 or 3 people to fully crew, they still have turrets, they move fairly rapidly and carry some inertia when they turn to give them a 'boaty' handling feel. Aircraft are still viable but compared to boats (as compared to tanks) they'd be made of paper.

'Water continent' (assuming it wasn't seamless) or open water areas would have water type bases - such as oil/resource rigs of varying designs which extended up above the water with access from the air; with capture points at the air pad, a couple of control rooms, the engine/drilling room etc that allows for infantry and air to play together, with lots of walkways and cover so that air isn't just able to farm. Bio labs could be structures that extend below the water allowing for tight infantry only zones with choke points - maybe that was easier to defend but didn't have its own spawn tubes (or you could cut the power to them from an external structure) so you could grind defenders down over time.

I'd like to see inland water areas too - lakes, bridges, rivers, anchored vessels, dockyard installations - all that could all allow air/boats/infantry/tanks to mix and fight over them.

I just don't think there's a real need to totally deviate from the formula and start imagining up new game mechanics - just some fitting base designs and vehicle designs would do it for me. Lack of terrain cover on the ocean could be compensated by speed and better AA. Lack of infantry fighting areas could be compensated by water structures that had plenty of opportunity to run around and get lost in, with indoor and outdoor sections and tunnels.