They are just not quick enough at tier 5 and above. Yes the torpedo aspect is good, but when an Aircraft carrier can do around 30 knots and your only doing 37 it is taking an age to catch up with them (im sure there are sums to show the time it takes to close 5km when only a 7knot advantage). Also the "camo" value I think should be increased - being spotted at 7km is still too far for effective smash and dash tactics - again because of the similar speeds of all tier 5+ ships (everyone does around 30knots) And when you finally get around 5km your completely beaten up and lucky if you can get one spread of torps before dying.
Im not saying their UP, but definitely not OP - I just think WG should look at the speeds and increase the differences between "classes"
I am not an expert in WoWS in any sense of the word, but feel the speed and camo gaps should be widened between classes.