I had the exact same problem in my 2008 MX-5. The top of the pedal travel was soft and clutch engagement happened near the bottom of the travel and was abrupt. I flushed the brake and clutch fluid with fresh fluid and clutch operation returned to normal and has been normal for two years. The fluid in the clutch hydraulics was ten years old and probably degraded and contaminated with water. Maybe try that first before buying new parts.