By “change the look and feel of companion”, do you mean, “require programming changes to the Companion which would render it incompatible with apps built to an older version of the SDK”? I can imagine that it might be literally impossible to build a Companion that is dynamically adaptable to the SDK version an app is being built to… although I don’t really know enough to say one way or another.
That said, I’m not sure why that, in particular, would be the primary obstacle. Companion is nice, but you can build and test without it. I suspect there are key SDK revisions that people would tend to target, so, worst case, you it might require building a small library of Companion apps targeted at those. A pain, but probably no more of a pain than building the core app itself to dynamically adapt to various SDK levels.
On that topic, aren’t there extensions which increase the minimum SDK level of the generated app, how does the Companion handle that currently?
FYI, my main app has over 200 installs by now, on devices running almost every possible version of Android back to 4.1, in countries all over the world… my #2 and #3 are Ghana and Nigeria (after the United States)!