I guess a weaker League One, implies a stronger Championship, so that's not great preparation. That said, if you put Man City in League 1, they're still Man City, it's not necessarily relative. Based on current form, if we sustained it (big if), it might suggest that we'd be competitive in a higher division playing at current levels. We just happen to be applying it against weak sides.
I'm not sure there's a choice, it's got to be harder to deliberately play at 80% to delay being tested in the Championship than playing at 100%, getting promoted and then finding that you're not good enough. The other factor is that next season there could be some big teams coming down (QPR, Watford, Sheff Wed) and up (Wrexham, Notts County). So whereas we might be one of four clubs capable of getting promotion this season - so most of those teams will actually get promoted - next season we could be a better side, but one of seven or eight and get squeezed out.