Defence token mitigation is a concept that has been around since at least wave 2, however, it has become apparent recently that many are not considering this in their fleet builds.
At its basic level it is very simple. 5 damage unbraced is better than 6 damage braced.
Ignoring all the circumstances of this, the game is fundamentally about pushing damage on to ships, higher the damage the better.
Now of course the game isnt that simple and you cannot just ignore the defence tokens. However, you can apply fleet wide methodologies.
Intel Officer and/or X17s.
Intel officers are often used on single high output ships. This is somewhat counterproductive as the salvo that they want to brace is the one delivered by this ship. You want the tokens to have already been put under pressure. The best way to do this is with intel officers across the fleet.
Works well with TRC corvettes, Ackbar assault frigates and DTT Arqs, all at long range. It also works with Mc30s, Raiders and Glads at short range.
Instead of your opponent using their brace/evade once per turn, they can use it only once per game!
This combines nicely with x17s. Just to strain their choices further.
Careful with x17s though. If combined with TRCs you may find your opponent redirects the trc shot and is unaffected by not redirecting the x17 shots.
Accuracies
The next method is accuracies. Simply keep placing an accuracy on their brace. Even with ECMs they will only be able to brace once, and afterwards the accs can hit the redirect instead.
If you can reliably bring accuracies to bear on everyshot, your opponent is going to have a tough ride.
Again, best to do this fleet wide.
Jonus, home one, h9s and sensor teams.
Overload Pulse
Niche option. It works, puts token under pressure and forces early discards.
Very simple, deliver a blue crit with Overload Pulse early in a turn. Follow up with damage from a lot of sources afterwards.
Not seen very often because it is tricky to coordinate. It is however, arguably the cheapest option.
Death by a 1000 cuts
Ye olde favourite of many.
Very simple. Instead of hitting hard, just hit the same target with many attacks. Defence tokens have finite uses, so make your number of attacks tend towards infinity.
Works well with TRCs and other small ship tricks as well as bombers.
Ignorance
This is the newish version. Ramming, APTs, ACMs, Dodonnas Pride and Luke are all very good ways of simply bypassing some or all defence tokens.
Sloane
Incoming wave 6, Sloane and boarding parties. I suspect this may become a subset of overload pulse.
Now, you may notice that I discussed how to mitigate braces mainly in this article. As it seems prudent to mention, these methods tend to work on scatter as well. Primarily their reason for inclusion in your fleet building methodology is to take out combat ships quickly and effectively. Their use on flotillas is a happy coincidence.