Depending on the complexity of your texture in AI, making a flattened version may be faster… I recently made a very complex AI file with a great deal of transparency and varied blending modes, and although AE would render it, it was very slow. I initially just made a proxy to use during animation work, but even the test renders were very slow. I made a JPG file that was 4 times larger than the original, precomped to make up for the scale difference (there was a close camera shot in AE), and it still rendered much faster than the original AI file. Typically, I like to leave items as vector, because that’s my specialty, but I just kept it in the project folder, in case changes were needed.
Rhett