I'm calling for a minor rules tweak that I think is in order regarding the Dolphin movement symbol, most commonly referred to as "swimming."
Figures that possess this combat ability are meant to represent strong swimmers, underwater breathers, and otherwise masters of their deep domain. Unfortunately to date the only thing the ability does is not hinder them in water.
It's a little ability to be sure, and those without it are forced to slog through puddles and ponds at the same rate as someone trampling through the underbrush. From that perspective the flipper speed subtype doesn't seem like much of a selling point because as written normal boot movement characters move through water with relative ease.
As a further insult to the aquatic acrobats the water terrain on maps is few and far between unless it is the major feature of a map. I'd like to suggest a possible change or two given the nature of what the speed type is supposed to represent.
For starters, I'd like to let all dolphin speed symbol characters break away for free from non-dolphin speed symbol characters, but only (you guessed it) when they occupy water. Someone like Robin shouldn't be able to tie up Namor or Aquaman in their own element... not while trying to tread water anyway.
Likewise Tiger Shark or Attuma should be able to dive below Hawkeye if not just backstroke past him with ease while he struggles to hold his bow and stay afloat. The purpose of the Dolphin symbol is to be able to swim circles around opponents, and this change helps them do just that.
This tweak gives a little more advantage to swimmers without being completely game breaking. I'd go further to suggest that Dolphin Speed Symbol characters can treat water terrain as hindering terrain for Line of Fire purposes, though that might be too much for players to fathom.
Hopefully the next starter set will make a Quick Change to the Dolphin symbol, effectively giving it a new porpoise.