The SNES installment, Ninja Warriors Again, was already on my shortlist for best brawler of all time. The second axis which gives "belt scrollers" their name was never what made these games interesting to me, and Ninja Warriors happily sacrifices it in favor of letting the player add up/down modifiers to their inputs. I think it's a good trade, and it was rare for any brawler to remain as consistently fun as Ninja Warriors Again over its runtime. Whatever problems you think might result from losing the "belt" are mitigated by the ability to block, and jump while blocking. The secret to the game's success was how different each of the three characters was to control, with Ninja in particular being easily my favorite "heavy" in the genre, unable to jump but given truly oppressive throws to compensate. On the other end of the spectrum, Kamaitachi is very fast but loses the ability to grab and throw enemies via traditional means (i.e. in the manner of a Final Fight character). Kunoichi feels more traditional and is a perfect on-ramp.

That's all regarding the SNES version, mind you. Ninja Saviors takes that version as a base, adds some tweaked movesets to round out each member of the cast, and adds two more playable characters. Raiden's not my favorite but he is cathartic, impossibly large, more like a showstopper boss than a player character. Wire-armed Yaksha is better. She has high maneuverability tied to a number of her attacks, but low maneuverability in a neutral state, so she's more technical and confusing than the original trio, and a perfect addition to an overhaul of a decades-old game.

People overlook Ninja Saviors, but it's honestly my choice for best brawler ever despite (or because of) its departures from the Final Fight/Streets of Rage blueprint. The only things I dislike about the game, honestly, are:

1. It hasn't been brought to PC, unlike Wild Guns Reloaded.
2. I strongly prefer the non-U.S. name (Ninja Warriors Once Again).