I recently finished "Dark Legacy of Shannara" and found it enjoyable as hell (esp how it handled my favorite character in the series), but yeah, I do agree he recycles ALOT of material/story.
If choosing to delve in Shannara, i'd recommend: Elfstones > Wishsong > Voyage of Jerle Shannara trilogy (you only miss out on Walker Boh's origins by skipping boring Scions Quadrology) > High Druid Trilogy > Dark Legacy.