Hoo boy, boss rematches. You know what game got those completely wrong? Megaman X5
You make your way to the final stage, walk into the first teleporter, and bam! Level 96 boss with a souped up healthbar. Not only do they take forever to kill, it's arguably a longer process using special weapons! Dudes like Mattrex and Grizzly bounce for like 5 full seconds after hitting them with their respective weaknesses. It slows the game down to the point that I don't like playing X5's final stage anymore, despite the final bosses actually being fun to fight. It's just a huge momentum killer.
I think the 'hatches' idea needs to be scrapped, and the old bosses should just be spread throughout the fortress like MM1/X1 did. This way it doesn't feel like a chore taking them down one by one. This would work even better if the games had larger fortresses, because you could start making bosses show up in like the 2nd segment, and be spread all the way to say, the 5th or 6th.
But it was also plagued with other problems, like a lack of (musical) atmosphere and tank controls, even though I don't think the latter is as bad as some make it out to be. Legends 2 fixed both problems and ended up being a bigger game, but it lacked the compactness of Legends' singular Kattelox Island and the interconnecting dungeons underneath it. I felt like it was a simpler, arguably more potent experience than the sequel.
Pretty much my exact thoughts on Legends 2, and why it's my favorite game of all time (despite the quirks). I did like Kattelox a lot more than the MML2 islands, if only because exploring a large singular island adds a lot more depth than visiting smaller sections of multiple islands. Ideally I'd like a Legends game that lets you explore multiple islands to the fullest, or at the very least have a singular large island with some climate/weather variance. It was nice to see snow in the beginning of MML2, as a contrast to the clear skies and green grass that were all over the place in MML1.
Definitely agree that the musical atmosphere of MML2 exceeded the first game's. MML1 had some nice tunes, but the way MML2 did it's music is what sold me. Take Yosyonke for example. The island has a main tune that you hear when exploring the town. You get a cheery version of it when entering a house/shop, a more ominous version when venturing outside the city, a more upbeat version of that tune when a reaverbot pops up, a straight-up remix for the abandoned mine, and another remix for Calinca Ruins. I think the tune is worked into the Train battle too. MML2's soundtrack was just genius like that; every island had its own musical atmosphere and the game was consistent with it!