Callas was not known for the timber of her voice but the dramatic use of it. In her later years, the voice really deteriorated. But her ability to dramatize still carried the day for her.
I hear you. I don't mind the fat Callas but her later voice just grates on me. Call me shallow. I have some great performances of complete operas (the ones that are acclaimed to be the definitive recording of that opera) on records but I can't get over her timbre.
BTW, this is just a personal rant on her voice. I just either click or not click with a voice emotionally. With her it's a negative click.

Just to let you know about me, I once went out on a date with a gorgeous looking girl a long ago. I never called again and even thought about ditching her on the first date/dinner. I couldn't stand her voice.