Some of them I guess it's kind of hard like lancer has a legendary jump distance so what else I guess you could just have another jump distance epic, Shadow has legendary stealth speed you could do an epic stealth duration maybe, juggernaut has a legendary shield durability can't really do much more but you could have an epic shield durability, Ares has shield durability could have an epic shield width maybe, zephyr could have epic shock duration don't know about that you already stay shocked for a pretty long time, Paragon you can just have one that makes them run faster, I don't have an aegis yet so I'm not sure how it works but if it takes damage you could have a legendary dome durability

And how come aegis doesn't show up under legendary ability cooldown or duration