Definitely jump range should be one of the balancing factors.
Otherwise, imagine all Federation strike force battle fleet taking a single jump from Sol to Achenar, or the contrary, why not? Or, just direct jump to Sag* A in your battle fitted corvette?=))))
Don't make that more arcade style as it already is.
You always have options: take a faster ship to travel, buy another military upon arrival if you are rich enough. Go in steady pace in your current overcharged build with all weapons/defenses. Or unload some of them to travel faster. In some realistic case being an attacker this gives additional amount of time for defenders to prepare - additional natural buff for defenders. Or just don't travel and be the king of the mountain in a given system if you are not capable at all to sacrifice some of your militaristic toys =) Boring? Travel in the bubble takes too long? But it gives an idea of the really waste universe around us and the real scale of all those "military" wonder waffles. I think many complains of that type will be negated in short term with the arrival of the possibility to call up for/reassemble your ship/fleet in the other system. Take a taxi or any other public transport (when it will be available), travel fast, then call for your ship.