It’s a good question, but I think the answer has to be “yes.” If Joon’s attack stat were to be increased by 148% for both tiles AND his special, he’d be hitting for like 2500 damage sometimes. (And that’s before accounting for the possibility of defense debuffs on the enemy.) I feel like that’d screw up the balance of the game quite a bit.
Why “titans excluded?” I’m under the impression that a 40% defense debuff on a titan is preferable to a 40% attack buff on your own heroes in all cases.
Regardless, I think @Garanwyn’s last post addresses the real issue: Since attack buffs are applied to a hero’s attack stat only for tiles, then the way it’s shown in the game is pretty darn misleading! I think anyone who looks at Joon’sattack stat in the course of a raid, and sees that it’s increased from 891 to 1069, would assume that the buffed attack stat would be applicable to both tiles and specials. Seems odd, at the very least!