...haven't thought through all the ramifications, but that addresses at least some of my concerns with the current system.
I suspect the main consequence is that a single detection range number applies to each object, rather than requiring a stealth adjustment. A corollary to that is that it's easy to display where a player has or has not detection ability in the GUI, without need for gradations or some other way to illustrate falloff.
A partial consequence is that anywhere you've got detection ability present, you don't need to re-sweep when detection strength increases. So, as long as a system has a populated planet with nonzero detection range, that systems is fully scanned every turn, without need to make a super-detection ship to move around after detection tech upgrades. Similarly, for systems without colonies, almost any ship (with nonzero detection range) is sufficient to re-scan at upgraded detection strength.