You are basically looking for what are often called "tactical RPGs" in the console world... the Final Fantasy Tactics and Disgaea series are similar in many ways, though not as tactically rich as Gladius. The Fire Emblem series would be another obvious place to look.
Fire Emblem etc. do NOT play like this game, there is no positioning, facing, or anything resembling real strategy, or even gameplay... You constantly have to abuse save/reload to even keep characters alive and to level them, and most of the games are completely unbeatable if you don't.
They are generic 'grind' 'RPG's pretending to have strategy in them because of the way they are presented...
UFO and Jagged Alliance 2 are by far superior in every sense.
If you've got PS3, valkyria Chronicles is an OUTSTANDING game with some similarities to Gladius, blended with a little third-person shooter though, set in an alternate 1930s Europe, try it out I highly reccomend it, or at least check out the board.