It's a bit unfortunate that we just changed the parametrization of SVC's gamma (from 0 to "auto"), but I just realized that using 1 / (n_features * X.std()) would be a much much better default than the current 1 / n_features.

Not sure there's a good way to change it though.

I wonder whether we should at some point do a breaking release like matplotlib did, but that might lead to more issues than it solves... (I kind of regret that we didn't change the cv=3 to cv=5 default when doing the model_selection refactoring).