This happens to be one of the game genres I enjoy the most. I’ll assume you’re asking about strategy RPGs, where you have to position your characters on a map to attack, and they’re affected by terrain, height, facing, and the like; in addition, they get stronger after successful battles. If you were interested in a different aspect of Shining Force, I’ll revise these recommendations.
PSOne games:
Vandal Hearts reminds me the most of Shining Force of all of these. It’s very early PSOne, and not as complex as many of the others, but has a great feeling of quick action, and it’s a great feeling when you set things up right. The combat system is rock-paper-scissors by unit type- magic beats armor beats sword, and so on. You have an army of up to twelve, and you field them all at once.
I recommend Kartia to anyone who enjoys the genre; I think it’s one of the overlooked gems. You control up to five humans dictated by the story, who summon up to ten monsters; if any human dies you lose, and if any monster dies you lose it for good and have to resummon one. Magic and items come from the same resource you use to summon monsters, and magic can alter the terrain, incuding raising and lowering it in unusual patterns. The monsters can be summoned as either rock, paper, or scissors, (common beats doll beats shadow) independently of their type and strength; humans are neutral.
Saiyuki was a very late-era PSOne game, based on the legend of the same Goku as in the Dragon Ball anime. Besides that it shares very little similarity with the series. All of your characters can transform into various animal spirits. Beyond that, though, I’ve forgotten most of the details except that the game was very good.
Other possibilities to look into if none of these sound appealing:
Final Fantasy Tactics (frustrating difficulty)
Front Mission 3 (sci-fi setting)
Vandal Hearts 2 (unusual turn structure)
Tactics Ogre (overly complicated)
PC games:
Vantage Master might be worth a shot. There’s no character advancement, and it is hard. The price is right though, if nothing else.
Here are some other PC options. (I love both of these games dearly, but they don’t sound like exactly what you’re asking for. You’re probably best sticking with the PSOne.)
Jagged Alliance 2 (modern setting)
Heroes of Might and Magic 3 (more strategic than tactical)