We'll first need to see if end up with a metagame where there's enough reason to justify running Exeggutor in Drago. The first attack along is not enough of a pull, because otherwise we would have seen Energy Hurricane Dragonite get played already and it really hasn't shown its face. The second attack has merit, but is at the very least useless in some matchups that exist right now. Right now is not the meta Drago with Exeggutor will be thinking about.
The one thing about A-Exeggutor ex is that if it does see play, the Drago mirror actually becomes really, really awkward. Like more awkward than it already is. Anything that isn't a 2-prize KO is now much easier to pull ahead against, and even something like Goodra or even Dragapult loses its merit as Giratina VStar and A-Exeggutor ex guarantee 2-prize KOs in some shape or form. If you use Rolling Iron to prevent your Drago VStar from getting Knocked out, well now the opponent just uses A-Exeggutor's attack to take something on the bench instead. Now, the person who used Rolling Iron is behind in the prize race and has to play to either take 4 prizes in 1 turn with Dragapult, or stop the opponent from attacking with a Regidrago VStar at all next turn. If the person who used Rolling Iron had used Giratina or A-Exeggutor, they would have been ahead in the prize race and taken out a Regidrago V prior. Goodra becomes a lot less effective in shifting the momentum of the game, and we'd likely see a lot of games that play out like a Raging Bolt mirror or Roaring Moon mirror where it is just trading 2 prize KOs with no other plan.