Yes, that would be the way to go. Treat all scanner types in the same way as shields are treated now. Only one type (as in old versus new) per ship, even though it should be clear that such a limitation is artificial (in both cases, shields and scanners), mainly for gameplay purposes. Then we would have a compromise without compromising either the new scanner suite or the old one. Co-existence in game but never in one and the same ship. Works for me.
In a way the main reason I even consider supporting the compromise was something Zijan said eariler. We have 80 types of weapons in the game... but only 2 exploration related scanners.
Things like the Xeno scanner are hard to count because, at least right now, they are used for exactly one thing - doing actively to Thargoid ships what we already passively do to human ships (if you can get within 500m of one). There's literally no reason to have one that I can think of unless you're specifically hunting for Thargoid data for some kind of tech upgrade - it's more akin to a Wake scanner than anything.