I've played both versions of Superstar Saga, and just finished the GBA version today. It was the last M&L game I played, though I had seen Youtube playthroughs of it as a kid. Playing it now, however, I find it to be one of the weakest entries due to its age, and the remake's faithfulness doesn't significantly solve its narrative and pacing issues.

To clarify, I still had fun. M&L games are never outright bad, and I'll acknowledge that this was a good start point for the series. For all of Superstar Saga's faults, it's absolutely not soulless. It's bursting with personality and has solidly humorous moments throughout. Plus, there are some characters I implicitly appreciate in the way you probably do, such as Jojora and her friend. If you played SS as a child and it's your favorite M&L game, you're absolutely entitled to that opinion. However, I find that there are a lot of flaws that soured the experience, and its successors have vastly improved upon the good aspects while filtering out what hasn't worked. It may be "unfair" to you to compare this entry to others since it was the first, but it is important to acknowledge when a series didn't get off on the right foot, because it learned from its mistakes.

Pacing Problems

In a vacuum, I'm a fan of Superstar Saga's plot. Cackletta and Fawful are a solid pair of villains that separate themselves well from Bowser (at least until one of them literally fused with him), and traveling to the Beanbean Kingdom with its charming visual style is a refresher from the same old Mushroom Kingdom. These are only overarching details, though. The actual pacing is less than stellar, with a bunch of small bossfights at the start and very few later. You fight Tolstar, Hoohooros, and Dragohoho within the first hour and they're all pretty trivial, with the first actually hard boss being Queen Bean (in the remake; original SS is really easy). The boss density slows in the middle chunk until you finish Joke's End, after which you fight all 7 koopalings separately (the thing Paper Jam did better) in the same single final area, and they feel like chores to deal with. Bosses should be at least somewhat eventful and serve a purpose in the narrative, but this game throws them out like candy sometimes, and it gets quite tedious.

The order of events is also questionable. After the Beanstar splits, you don't immediately go after the pieces. You spend a good chunk doing essentially nothing of importance, escorting Peach to Little Fungitown and getting a cure for Mario's bean virus. The Beanstar pieces aren't relevant until Bowletta orders you to get them, but that goal should have instantly been in the interest of the protagonists rather than them conveniently ignoring it until the plot remembered to exist. The Beanstar piece search itself isn't well-executed, either. The first piece is way longer than the others due to you having to learn the combo Firebrand and Thunderhand overworld moves, and the other 3 are glorified sidequests with no weight other than the trivial solo Popple fight. People say the search for the Ultibed pieces is boring, but it had solid character moments between the partners, and the locations didn't just feel random. In comparison, the Beanstar piece search feels completely tensionless and immemorable.

Characters

Man, am I glad partners exist now. Barely any of the characters in this game are memorable outside of the villains and the trio in Beanbean Castle. Everyone else is met in a single area and not relevant otherwise. Bubbles only exists for Chuckolator, his egghead brother only exists to force you to go fruit-picking, the snails do nothing, the beach astrologers do nothing, the skeleton pirates do nothing except die comedically, etc. You kinda have to like them off a gut feeling or otherwise ignore them completely. One-off side characters are totally fine, of course, but they need some degree of an entertaining personality to stick, which is why Harhall and Jojora are actually memorable. Otherwise, side characters were way better-balanced in future entries.

Cackletta's Soul

Good lord, this fight is unbelievable. In both the original and the remake, the fight is a massive spike in difficulty from everything before it. You start at 1 HP because that's totally fair, meaning use a max nut or die instantly to her first attack if you're slower. Particularly in the remake, your damage output is just far too low. Even matching her level of 40 (a jump from everything else in the area), your strongest Bros. Attacks won't deal much more than 100 damage. Compare that to her heart with 1280 HP and the multiple 300 HP limbs, and you'll be here for genuinely over an hour avoiding attacks and slowly getting past her ever-regenerating targets. I get what a final boss is, but there's a huge difference between hard and a complete slog, and they really didn't need to make it this ridiculous. I'll at least credit the original for not taking as long, but it clearly had the same spike in difficulty given the start, the attacks, and the heart being the only thing that didn't have a massive HP increase in the remake.

Conclusion

To wrap things up, again, you're free to like SS and I don't aim to ruin your experience. It just wasn't able to click with me, and ultimately earned the title of my least favorite game in the series. Playing the GBA version over the past few days felt a lot emptier than even the infamously slow Brothership or the unoriginal Paper Jam, much less games like BiS or Dream Team with their excellent character-driven entertainment and difficulty scaling. I just barely cared about anything that happened, and while the battling was still fun, that's the bare minimum, and the gameplay additions of future entries make them superior in that regard.