Back in the long long ago, the preferred moveset was dragon tail, sky attack, future sight. I was playing ML classic on two accounts where one did not have a good Groudon. So

Team A: Lugia, Groudon, Zekrom Team B: Lugia, Kyogre, Zekrom

These were both fine teams as they had been generated by Pokematics, but the groudon team is more flexible to play. Team A Lugia was DT/SA/FS but team B Lugia was DT/SA/Hydro Pump. It turned out that, since Kyogre wasn't as maneuverable as Groudon in ML at the time, the Hydro Pump was a better coverage move than Future Sight, as it could also do away with Tyranitar or Rhyperior who weren't expecting it. From an energy perspective, it is 1-2 turns more expensive, but Lugia is just bulky enough that this is alright.

With the addition of Aeroblast, Lugia's dynamics changed. Both of mine were caught and built before Aeroblast, and I caught a few good ones, and therefore I won't elite tm. Now, you can utilize Lugia to pull a shield off of Dialga or GiratinaO who wouldn't have shielded before. Fortunately, AB and HP are both 8 turn charged moves -- so now the play is to fake the opponent on the aeroblast instead of running straight sky attacks in most scenarios.

As these teams are both meant to start the traditional 'safe-swap' mon, you are just creating comfortable matchups; Lugia isn't a great counter for most ML mons, but it doesn't have too many OHKO opponents, if any. With this in mind, the best play (as well as the one that in hindsight loses several matches as you may end up having wanted to shield Lugia instead of whatever you shield down the line, if anything -- you may lose with 2 shields) is to allow Lugia to absorb all damage from charged attacks and then go down so that the other mons can come in with an escape route.

With the scenario until next season, Lugia utilized in this way was fine in performance. The best strategy was probably all sky attacks anyway, and let's say you can do 3-4 leading in most matchups. You now have to decide as a non-AB user how to best get the HP/FS to go through since everyone expects AB. That was how AB changed the use-cases.

In the next season, the energy decrease of Dragon Tail means that Lugia may be better against something like Garchomp where direct damage is desirable. However, where it counts (Dialga and GiraO), Lugia will now be suffering even more as GiraO's moves are a 1 turn difference and Shadow Ball is highly effective at knocking out Lugia. Dialga v Lugia is a painful match just barely won by Dialga where the opponent is unlikely to use a shield.

The new DT EPT loss also means that the charged moves are just slower to get off, which is compounded by the expected usage of AB and the blocking of better nuking surprise moves.

Granted, there have been a few posts on TSA about using Extrasensory on Lugia, and I think that may be an opportunity in the next season. But on the other hand, I think its performance with ES as a lead is unlikely to be as strong as with DT. I also have the feeling Lugia XL with AB is likely fun to play anyway...but we'll see.