You want me to provide arguments for what? Why I like Grimoire? I think I already did that.
If you mean why it surpasses Wizardry, I never asserted that. Wizardry, in my mind, was the first and will always be the best. 6,7 and 8 were incredible games. Cleve himself has acknowledged that. Hell, those games are why he made Grimoire in the first place.
If you're pondering what specifically it is people like me see in a game like Grimoire, that's rather hard to describe. I can only provide an anecdote:
Once I got past the technical weirdness of Grimoire, I felt like I was transported back to being sixteen years old again. Actually, at one point, I had a cup of coffee while I was playing it, and I sat back as a combat encounter was beginning and I had issued my orders, leaning back in my chair to watch the results unfold. It just sort of hit me then. "This is what I love about blobbers." Real blobbers, that is, turn-based combat-oriented games that force you to make decisions, hit a key, then sit back with your cup of coffee and hope you don't get your ass handed to you. That is what a blobber and therefore a game like Grimoire means to me.
Is that what you wanted to hear?