>>53614738Fair warning, Riolu/Lucario are endgame. Also, it doesn't have all that many more Pokemon, just gens 1-3+riolu's line+crossgen evos like Honchkrow and Sylveon.
That being said, while Blue Rescue Team is rough around the edges (gen 3 movesets being tiny, teambuilding being cumbersome), it may be a little hard to go back and play Sky later down the line due to how many things changed since then.
Original/Remake are both wildly different with how they play, and I wouldn't say that one can replace the other. If you're curious but also a cheapass, emulate Blue and see if you like it. Both the original and remake are good games, so if you like roguelikes you'll probably like them.