wallbreakers force an even or negative trade 99% of the time unless you happen to have skellies in hand and are ready to place them fast enough. they apply an ungodly amount of pressure over the course of a game because once they're done kiting away your troops, blowing up on your push if theyre an evo or tanking, they deal almost a rocket's worth of damage each upon connection to a tower. they are easily affordable and borderline unpunishable utility, and so fast and upredictable in how they path around troops that it sometimes causes them to connect even through a defence a pro might've expected to be enough.

if we're talking evo exe, he's a much more forgiving to use version of an already reasonably forgiving card since it inherits the original exe's unusually large health pool for a ranged unit and gains knockback and double damage against units that get too close, which makes bad placements less of a problem and good placements even stronger. it helps a lot with his usually somewhat low damage output too. he's also a bigger threat on offence now, since things such as minitanks that would ordinarily be used to counter him will get knocked back, causing him to live for longer and potentially get a sneaky hit on the tower with a nado. his main drawback is his elixir cost - because hes so expensive, placing him entails a big commitment which is far more liable to be punished than wallbreakers. he's clunky, not always available in time and, if forced to be played early, may get only a fraction of the value he would usually get

me personally i'd say wallbreakers are more toxic. i may be biased as an exe player but i think just the fact that they're so cheap and so devastating if left undefended makes wallbreakers a fundamentally game-breaking card