I can live with all but the Elite bonus for Plat being equal to Gold. No road warrior would give their bag to an airline anyway without it being absolutely necessary so the checked bag thing isn't that bad, at least for me.

Only getting miles flown only has little effect on me but
I find making the bonus miles for Plat and Gold the same insulting. Why become a Plat? Maybe just to get slightly ahead in the upgrade queue.

Theories on CO's reasoning have been discussed here but as a long time Plat member my intention is to write an email to CO to voice my displeasure with the change. Such petty changes make it harder to choose CO since the benefits of doing such are disappearing fast.