Of course Transformers 2 is an art film. It's an exercise in pure chaos, and experiment pushing the very boundaries of absolute Dadaist expression. Any compromise he might have taken- by adding a plot or interesting characters- would have lessened this monumental achievement. All his career has been leading up to this work, and all his other less chaotic works were merely practice for this, his masterpiece.
(Boy, can I lay it on thick. That's how I got my film school A's, folks.)