At the same time as we release Piwik 4.0.0, maybe we could also allow Custom Dimensions values of any size. See: https://github.com/piwik/plugin-CustomDimensions/issues/79
(since it will require a big schema update, we should do it as the same time as Piwik 4.0.0)
Of any size is not specific. We could maybe set it to 500 or so. But this obviously limits how many custom dimensions there can be in total.