Dark Savant is the only Wizardry game I've played, though I've seen bits of footage from the game before and the game afterward. 7 appears to be, at *most*, a slight graphical upgrade from its immediate predecessor, and substantially less graphically impressive than 8.I, however, am a firm believer that graphics do not make the game.
What Dark Savant had for me was replay value. I've beat the game in different difficulty settings, with different characters, and different skill sets. I've solved the puzzles using only the maps, then gave all the maps, split more or less evenly, to the surviving NPCs, to see what they'll do. I've gone back to the game with the express purpose of mapping every possible inch of the game. I've spent more than one run trying in vain to find the "Red Mountains" advertised on the map provided with the game. I've played games killing all the NPCs, or alternately siding with the T'Rang, the Umpani, or as close to both as you can in a single run. A couple things I *haven't* done yet are to beat the game with one party member, or to beat the game at a very low level, without any class changing.
TL;DR: I play to see what I can accomplish in the game. Also, the plot left me deeply immersed, and Guardia let my imagination run wild, so much so that I actually had dreams of what happened in Guardia's future.
This is one of my favorite games to play, even after all these years (along with Morrowwind and Civs II and IV). That being said, there are annoying aspects of Dark Savant. The mapping system is really irritating (though I feel I've been spoiled with other RPGs regarding that). NPC dialog eventually felt a bit flat, once I tried asking different basic questions to them. Character creation was probably the worst, though. Did it ever seem to anyone else like the game didn't want you to ever make Monks, Samurai, or Ninjas from the start?