hmm im not sure. suppose whole team picks yamato, no chance getting anywhere near the base..
if it will get 'famous', lots of ppl will start picking it and just image what would happen in the game full of yamatos... fuc...ed up.
in my humble opinion after some thought, i think that the cooldown is good as it is right now. although i only find lvl 3 yamato's cd a little too much but im not sure about that one.