I don't expect the battlefield rules to go unmodified for more than a turn, so having a neat concept play out once or twice doesn't seem like that big of a deal. If both sides get to change the rules once a turn, we're going to roll through options pretty quickly if both sides shift everything
but the map. And if it doesn't work?
If you don't like how something works, go ahead and Shift it.
The first point is entirely reliant on the writer anyways. The
battlefield might become plain, but that isn't the
battle.
The second point isn't our concern as stated in the OP. I think Fal has made it pretty clear that anything we toss into the blender will be(rightfully) picked over with a comb.
Yeah, I get that those are concerns. Entirely valid. But I do they look more like concerns from a gm's own experience and player blurring the lines they should be thinking along a little bit. Fal might not see things through often (not like many of us do), but I do at least think what they
have done shows an ability to keep things interesting. There was the one discord-run one back in the old days that had some halfcocked movement mechanic for the bases, but it was still interesting.
tl;dr I think you're putting too much stock in the longevity and reach of Shifts, and my opinion is we
should focus more on the temporary, short term fun stuff. We're not setting rules in stone, so we aren't defining the entire game. We should take this opportunity to fiddle with an arms race like this, I think, since it's not like we get this ruleset often (or Arms Races often, either).