Of the four versions you posted, James Taylor is the best, but it’s a far cry from Glen Campbell’s. The thing about an intimate song like Wichita Lineman, it’s got to be personal and affecting without copping too much of an affected style. In other words, it’s got to sound genuine and heartfelt, and while the tune seems simple and easy enough, it needs a great voice to pull it off. For example, Tom Jones has a great voice, but he makes Wichita Lineman sound like Tom Jones, when Tom Jones should be trying to sound like Wichita Lineman, if you know what I mean. :-)
I’ll offer these two versions that I think are quite good, and maybe you can tell me what you think. No, I don’t think they’re as good as Glen, but I do think they are good:
Cassandra Wilson
http://www.youtube.com/watch?v=lWwDgYlGeZA&feature=related