That's just one example build, and like Thani said the death arrows aren't the only thing that proc the crit chance. Basically if I have a chance for one out of 5 successful hits to be triple damage and knockback strikes, that's OP as all hell, no debate there.
Regardless, if you have a ton of damage on your character you could essentially make a 20% move hit for 40% damage, or make a 15% move hit for 30% damage. That's insane, that cuts the moves I need to use to knock my opponent off the stage in half. I don't see why people can look at that and say "Yeah a simple tilt move being able to do more than a Smash move without stats is totally ok."
Is it because of the defense decrease when you have a high stat in attack? Well lemme tell you something, it doesn't really affect much. Basically here's how the meta for equipment would be
1. Someone has a High Attack stat and then someone counters with a High Defense Stat build. The stats essentially in theory cancel out and equipment does nothing
2. Both players build High Attack. Well in this situation matches are INSANELY quick and INSANELY boring and anti-hype as both players take like 3-4 pokes each to kill each other
3. Both players build High Defense. Well now we have a boring slugfest where no one does damage and no one has any speed of any kind, and the match is a snoozefest
4. Players build differing builds ie. Someone builds a hybrid build with mixed stats and another person uses a really defensive or a really attack based build. Well really, what's so interesting about this? So a high Attack build still does solid damage even after the Hybrid build's defense is taken into account, but then the Hyrbrid build's Attack stat - while lower - can take small advantage over the Attack build's low defense stat... But then... If Hybrid builds are clearly superior, then lets assume the following
5. Both players build hybrid stat builds that are balanced and only increase each stat slightly. Well now we only have slightly beefed up characters, and while this is the most interesting case scenario its also the only one that is actually an OK scenario. But if that's the case we only have slightly beefed up characters that just hit slightly harder... But wait the Defense stat makes them take less damage so that kinda cancels out... I guess the characters move a tad faster (assuming their silly enough to even build speed) so there's that, but I really don't see the point at that point
So really, unless scenario 4 and 5 end up mixing together and the meta actually diversifies, equipment won't do anything but make matches lamer, at least in theory. I'm all for tournament testing it out in the ruleset so we can see what equipment does with more certainty, but right now I don't see the point, and I can only see the mostly negative affects it could have on the meta