Saw them last night at Prudential Hall in NJ. While the vocals crackled a bit after 40 years of performing, the evening was a clear reminder of the sheer musicality and genius of this band. I grew up with all of it, the fantasy-driven excesses of Zeppelin, the blues-metal onslaught of Deep Purple, the epic works of Yes, and so on. But I'd equally put Tull in the category of ground-breakers like King Crimson, the Stooges, Fairport Convention, and Ten Years After; and while Tull's work is absent the brooding, teen-angst self-pity of Joy Division (no disrespect, I'm a big fan), you hear the praise for the influence of JD on ensuing groups and I'd argue that Tull's influence was no less profound. They showed that rock groups could be literate and articulate.
No question, they should be in, but this is less a tarnish on Tull's reputation as it is on the Hall's.