What's wrong with the control arm?

Nothing is "wrong" with it really, except the track changes (albeit slight). I'd prefer an upper adjustment instead.

I would also prefer an adjustable upper arm instead of a lower arm. I'm a bit surprised there isn't one out yet.

Changing wheels (or swaybars for that matter) does not affect the alignment.

Changing crash bolts, struts and or springs will require an alignment since you are undoing alignment bolts.

I just installed the OEM crash bolts. Prior to doing so, I checked alignment, and then checked alignment after installation (using the string method). The front toe may have barely changed, if at all - it was easily within range of measurement uncertainty using a mm tape measure.

I measured the factory alignment to be toe-in on all 4 corners. Actually, it was very similar to Dezoris first alignment in his Alignment FAQ, with the driver rear showing about 2x more toe in than the rest. Both fronts and passenger rear were ~0.12deg toe in, driver rear was a little less than 0.24 deg toe in.