We had to gut the particular pages that we cared that ranked on Google properly. Our tire shops still get punished for slow page load times. We were using the intrinsic SKU/Attribute mappings the way they should be done but now we are rolling each tire size out as their own products because we can't map product variants to categories specifically and because of the load times required to cache (and re-cache) the enter product catalog over and over again recursively. Converting many of the temp tables procs to CTEs and other optimizations helped but not completely.
I just get the feeling that speed needs to be the #1 issue that gets tackled in 2.0