I had this same idea! And I'm happy to see that I'm not the only one who have thought of it. In every old game entering water would mean instant dead, same as in w:a. Later (with better engines) they have added the swimming and diving possibility.. i.e. Half Life 2, GTA San Andreas...
Dunno if it's possible to make a difference between floating on water and diving underwater, 'cause in that case, if someone plops your worm and he had enough health to live, he could float on the water until his turn comes and then swim back to the ground or w/e.. And when they're under water, there could be a timer of how long they can "hold their breath", like fuel on the jet pack, i.e. they can dive for 10 secs and then must come out to "take a breath"..
I believe that this feature would bring a lots of new ideas for some new ways of playing, new tactics etc..
Might be cool if worms had a diving equipment like Aqua sheep, diving mask and a breathing pipe.. Tho it's not necessary..
Good one Steps!
p.s. I agree they're diving too fast on that video example, it must be slower..
Weeeeee, worms learning how to swim!