No, that's the thing. In Smash 4, most of their balancing was complete bull**** with almost no rhyme or reason. Greninja started out with a glitch where he could actually shadow sneak out of his moves to negate endlag. For example, he could Dair into the ground, then shadow sneak to the side to punish a punish. It was cool, but admittedly unfair. They patched it out, then proceeded to nerf his damage...then did it again....then nerfed the knockback on some of his moves....then added some lag to other moves. The sad part was that he was NEVER considered high tier in Smash 4 at any stage other than MAYBE the very beginning yet they continued to bash him into the ground, hence the internet meme "Better nerf Greninja". It was like a run-on joke that with every patch, there was an obligatory Greninja nerf. Meanwhile, you had characters like Cloud and Bayo that went on to completely dominate the competitive scene with little to no meaningful nerfs at all (likely to promote the sale of their DLC). Several heavies even took nerfs despite never ranking more than low tier. Don't get me wrong, Smash 4 had the best initial balancing of any Smash that proceeded it, but as time when on, I couldn't really see a coherent rationale for how they chose who to buff or nerf. Ultimate is undoubtedly the best balanced so far, but as Sean^2 stated above, we don't really know for sure what kind of methodology they're going to use moving forward.
Dude, Greninja was only nerfed twice and it was NOWHERE near as bad as people say:
Up Smash took a heavy nerf due to the changes in hitbox that messed up the sweetspot on platforms, and became harder to use as a combo-linking move (wich still can be done at low percents and I personally think it should have gotten a bigger endlag nerf, it feels unfair to allow a move that deals ~20% damage to be able to combo/string into itself), but the KO potential was untouched and is still one of the strongest AND safest in the game.
Up Air became unreliable for killing, but the drag-down spike pseudo-infinite combos (ironically the ONE thing they wanted to remove) were unaffected, you can still combo from 30 all the way into 90 with it if you follow the DI perfectly.
Down Smash got lower knockback to compensate the damage increase, even if the official wiki considers it a nerf, the overal KO potential was untouched.
Fair lost a lot of KO potential, wich admittedly was unwarranted considering how laggy and commital it is, but it was latter patched to work better as a spacing tool. And now in Ultimate, we got the best of both words in a devastating move (better range, even better KO potential than pre 1.0.4, more damage and they fixed the blind spot) that is a a "Well, duh" for potential nerfs, as any Greninja main on the forums will tell you.
Hydro Pump became a little less infuriating to play against for half the cast, wich was completely warranted, the gimp/kill potential of that thing pre-nerf was just ridiculous. And in 1.1.5 it got a critical buff that turned it's main downside, the headbonk, into an upside. With the lower angle, you can actually intentionally slam into the walls, and then do a wallcling into a jump in some stages to get EVEN LONGER recovery distance than usual.
Shadow Sneak lost two useful glitches (dair lag cancel and dashing sneak), but was compensated in knockback.
From patch 1.0.6 onwards it's all buffs on a multitude of his attacks, mostly on the knockback of his Smash Attacks (Including Up Smash for some Arceus-forsaken reason), a rework on Down Throw to improve it's combo potential, and general lag decrease on miscellaneous moves.
And in Ultimate, we got a reverted Up Aerial that kills even earlier than before, connects reliably into the final hit even with rage (the main nerf it got in 1.0.4) and has a even better potential for dragwdowns with the reduced lag, improved hitboxes on all the Kunai-based attacks, even FASTER speed, TWO new kill throws (Bthrow and Fthrow that now kill earlier than Uthrow at the ledge, while still being great for positioning and edgeguard setups, especially with the new Shadow Sneak and Fair), a functional counter that kills off a JAB at 70% (or even at 30% if it catches you high up in the air or the semi-guaranteed Uair follow-up connects) and has an OHKO spike to destroy any recovery with hitbox, a reliable and safe high% kill move in FTilt, a combo Dash Attack that rivals pre-patch Meta Knight's, a faster (but laggy) grab, and Hydro Pump and Dair now keep the midair jump for later, making the Headbonk exploit mentioned above even better and allowing Greninja even flashier aerial combo attacks. Oh, and grounded spikes are no longer techable, so, good luck getting out of the Dair kill combo now.
Granted, they nerfed the funniest move in his arsenal, the Down Taunt can no longer true combo into Uair or USmash at kill percent like it did before, but with the new Fair turning the former from a 50/50 into a deadly frame trap and the latter having an improved hitbox that can frame trap on itself (because USmash wasn't good enough already, it now beats airdodges even better, including directional airdodges), and still being usable to bait opponents and cover yourself from some projectiles when charging Shadow Sneak, this is a mere technicallity.
Just check the patch notes yourself if you don't believe me:
https://www.ssbwiki.com/Greninja_(SSB4)
https://www.ssbwiki.com/Greninja_(SSBU)
As for the meme, we now use it mostly as a rallying cry on his amazing new potential, as well as to mentally prepare ourselves on a likely future nerf of FSmash, USmash, Shadow Sneak, Uair, Substitute and Fair, wich every Greninja main agrees are completely busted.
