When you are about to go up against a shifter you know exactly what you are going to get, making it quite easy to plan for.

I was thinking about a series of edges, top end expensive edges, where the shapeshifter can discuss with his guildmaster and learn, for their top end forms a new skill/ability or a general bonus.

Things like:
small % increase damage edge
small % increase evasion edge
small % increase dodge edge
ricochet skin already exists to help carapaces etc with deflection
run
variousblends
forage
scatter

Just so that when warrior A sees shifter B in his tiger form he might be surprised that this one can run or forestblend or hit harder, dodge better. These can me as expensive as you need to make them if you think they might be OP but I don't think they would be, mutually exclusive to each other and/or certain forms could be excluded from certain ones.

Just might bring a little sprinkle of variety to the class and cause a few ppl so think of saving some edge points for this and less on spin the wheel/roll the bones when the form is not their No1 choice.