It's actually not that simple. If you are on an easy shard where no one changes their reinforcements, then you can probably win 75-90% of the time. If you are on a shard where they change their reinforcement orders then you have to guess correctly what their reinforcements are and it's back to a coin-flip the first battle and if you guess wrong, you will know the reinforcement order and can win the 2nd battle. If the 2nd reinforcement is Mk6, you bring out scimitar as your first reinforcement and you wait until just before their Mk6 comes out and stealth your fleet so that their Mk6 can only target your Mk6. If their Mk6 nukes one of your ships, you can time out. If they use ES as the 2nd reinforcement, you need to bring your bomber out 1st because you need concussion mines to take out the fleet since ES regenerates health and protection for their fleet and scimitar doesn't have enough firepower and you can time out.
The solution is not to use the Leviathan to counter the Leviathan. Use the Profundity with Mk6 as your first reinforcement. It has over a 90% win rate and it doesn't matter what the reinforcement order is.
The Leviathan is a product of poor testing because it's now such a bad counter to itself and I think the complaints are warranted.. I'm fine if they don't fix it because given their history, the fix is probably going to create new problems and maybe it will be worse.