Striking Scorpion probably but I also think it would be really fun to play as a Swooping Hawk, depending on how they handle aerial movement. I'd be all over an Autarch class as well.
Fire Dragon This isn't fluff friendly. Aspect warriors don't drive. I would suggest making driving vehicles an option exclusive to guardians, because I personally would want to see more than just aspect warriors on the field but staying as a guardian would need incentive, being a vehicle+heavy weapon operator would be that incentive. Funny thing, the fluff was recently change or 'clarified' so that now eldar are generally more skillful but not quite as powerful as human psykers can be. Having said that, it doesn't mean eldar psykers aren't powerful enough to pop a marines head but who knows.
May not be fluff friendly, but neither is changing classes, need to balance gameplay as well. Some vehicle and class restrictions can be expected, but everyone at least needs a bike to get to combat.
I understand that there may need to be compromises. Will see. Class changing though is quite fluff friendly , since it's only the Exarchs that get stuck on any given path. CompositeGNFNR said something like this but I'd like to bring it up as an option again. Making becoming an Exarch of an Aspect in some way a very significant move. Maybe make it a permanent state for that particular character, meaning you'd need to make a new character if you wanted to try something else.
