I think the current plat for life is great marketing:

It commits people. Imagine for example people who have done a lot of flying over a lot of years, who fly less now, and who only have a few years to go until plat for life. Perhaps it sounds far fetched. But sustaining 10 years of easy requalifying is not easy, even not with carry over miles. For example: People can have a specific job for say, 7 years that involves a lot of flying, then they cange jobs and fly a lot less.

Actually I see it happening around me with colleagues who changed jobs within the company. I've had lunch discussions about it! They book extra J flights privately or choose AF over SQ etc... just to re-qualify platinum with the objective to reach plat for life.

Or in other words. With the relatively low thresholds compared to the competition, it is feasible to fight for it. It makes people spend more at the airline than what they otherwise would.

I would suffer very much. I would loose the following benefits which I use regularly:
-No more partner platinum card through American Express
-Paying extra for seat plus
-Less bonus miles
-No more dedicated and very efficient platinum helpdesk

So no, thank you very much, bad idea!