A collection of information on the vi editor.
An Introduction to Display Editing with Vi by Bill Joy (creator of vi) and Mark Horton.
The Berkeley Vi Editor Home Page – website of the nvi editor by Keith Bostic.
vi Complete Key Binding List by Thomas A. Fine.
Your problem with Vim is that you don't grok vi. This is not a dedicated article on the vi editor, but instead a very elaborate answer to a question posted on Stack Overflow. Yet it is one of the best explanations of the principles of the (original) vi editor I know of. Highly recommended.
The nvi text editor by Matt Widmann.
edit text with vi(1) by Roman Zolotarev.
vi is not vim by Hugo Daniel.
Why, oh WHY, do those #?@! nutheads use vi? by Jon Beltran de Heredia. Based on Vim, but most applies to vi as well.
Grokking the Zen of the Vim Wu-Wei by Jeet Sukumaran. Based on Vim, but most applies to vi as well.
Vim still sucks by Greg Alexander. I don't necessarily agree with everything in this article (I was a long-time user of Vim myself), but it is nevertheless an interesting reading.
Learn Vim For the Last Time: A Tutorial and Primer by Daniel Miessler.