As far as Monoscope and Grid are concerned, I agree with you 100%. The new layout/design is simply awful and doesn't convince me in slightest. It would be great if the familiar layouts/designs could be brought back as alternatives.
As for linearity, I’ve never really used the Circle pattern, since CRTs in particular completely mess it up. What’s the point of seeing a perfect static circle if the whole thing gets distorted again when it moves? There’s nothing worse than when a scrolling image stretches apart in the middle and compresses at the edges. In that case, I’d much rather have a “distorted” still image that scrolls without major distortion.
But yes, in the end, you could add an option in the 240p test suite to display the “legacy” test patterns instead of the new ones.