I would agree that Hero's critical hit Smash Attacks
can KO at ridiculously low percents, but the situations in which this comes up is about as ridiculous (broken shields, or low-level play of "Throw It Out There & Watch 'em Roll Into It"). Any heavy-hitter will be able to do that ... and they do it consistently without having to gamble the KO away.
Take a heavy-hitter like Bowser or DK, reduce their massive KO power with their strongest attacks, but then give them a 1-in-9 chance to hit with x2 Damage and see if people who main those guys like it. No, they wouldn't, you know why? Because heavy-hitters already KO just fine -- dealing ~100% damage with a massive hit might be fun for giggles at first, but you quickly realize that it's unnecesary, and it's waaaay better to have a fast-hitting attack that KO's with 16% damage 9-out-of-9-times, instead.
Sakurai (and/or his dev team) made Hero a "heavy hitter" that falls short of actually being a heavy hitter 8-out-of-9 times, then they "balanced" him with an overkill attack 1 out of 9 times.
The same thing can be applied to things like Hatchet Man (which is
always ridiculously powerful, but is laughably unlikely to hit raw in competitive play) and Wack/Thwack. You have to get the opponent to about 100% just to have a 50/50 chance of a KO. A competent heavy-hitter will be going for
guarenteed KO's at those damage percents, and will often enjoy KO's below 100% when fighting anyone who isn't a heavyweight themselves.
The only reason why Hero works as well as he does is because his
full kit, when worked together in an intelligent manner, can often set up situations where his strengths can come into play
and because Hero also has access to Specials that are
not RNG (Frizz/Zap/Woosh): Shield Breaks and Snooze can set up for Critical Hits, Acceleratle opens up mobility/combo game, and Psyche Up allows him to become a true Heavy Hitter without needing RNG (for a single hit).
Would Hero be OP or at least Top Tier had he not become memed with RNG (and given top tier FE frame data)? Quite probable. Would he be as fun -- or would he cause as much saltiness? Not nearly.
In the end, I am perhaps more satisfied with our "RNG Hero" that we have than had we been given yet another generic swordsman whom had nothing to let him stand out from the rest aside from his historic game series.
