Have to disagree here.
My only slow defense isn’t doing any worse since they removed the 20% stat boost.
On offense most newer slow heroes are good to great, but also older ones either with costumes or high emblems are still useful. Probably a third to fourth of the heroes I use every war are slow regardless of the rules.
I mean I can understand that someone doesn’t like slow heroes, and some are just “useless” outside rush or at least extremely outdated. But with all those new extremely hard hitting heroes in pvp or war defenses I’m relying more and more for slow heroes, because unlike my fast or very fast they can survive when the defense fires and are powerful enough to counter whereas if I take some only fast heroes I’m extremely board dependent. If the start board isn’t good I’m most of the time dead, when the defense is charged.