Well the Autarch set up is rock solid
I would drop 1 of the fire Dragon squads bump the other up to ten and give the Exarch a firepike and tank hunters and that will massacre ANY tank. If you feel it nessesary add holo-fields to their transport because opponents make them a priority usually but not nessecary
Howling Banshees...never liked them much...always liked scorpions much better and scorpions are cheaper for a full squad with no need for a transport
Use the points you just freed up to buy a full 5 man unit of Shining Spears (they come in sets of 3 so the extra one can be used for bitz for the autarch)
Never, EVER under estimate Shining Spears (most of the people I play have and have payed dearly) They are fast and versatile one minute you can use their S6 lance weapons (add the Exarch's S8 lance) and they are very capable of tank hunting, they can glance 14 armor, but shouldn't have too cause of their speed (Exarch Star Lance is a bright lance but with shorter range) And their legendary charges make mince meat of Guardsmen and with withdraw they can keep charging right in
The guardian jet bikes are ok, I never liked them but its just personal preference. 12 guys with 4 suriken cannons is hard for any army to swallow though. maybe cut them down too 9 guys with 3 shuriken cannons and use the points for either a 2nd dire avenger squad so they can mutually support each other or a squad of guardians with a scatter laser, OR a squad of storm guardians with 2 flamers and a warlock with enhance and conceal (my personal favorate)
Overall eldar are fun and extremely flexable
enjoy