Overall, while it is always disappointing to have negative changes, I'm not too disappointed with these changes.
I'm glad Eligible Sectors is no longer required. Lately, DSCs and Family pooling was easily getting my the SCs requal, but stretched to even get 8 flights annually lately, without a Status run.
While I probbaly think the SC earn rate is generally a poor rate compared to the zone buckets, I don't mind that the SCs per $ spent does seem a bit easier to work out: it's a simple calc to say "I need to spend $9.6k with VA to maintain Platinum", and track spend along the way. It would be handy though to be able to see the various Economy fare buckets and choose which one you want to purchase, rather than it showing the cheapest available in the fare category. You may want to spend $24 more to tip you over those extra 2 SCs you need.
I can't see myself maintaining Platinum anymore - I doubt I'll spend $9.6k per annum with VA in the coming years on my changed travel patterns of late. However, I am very glad to see Forever Gold introduced, and I am very hopeful to qualify for this. With LTG on QF already locked in, I can now go back to choosing either QF or VA (with QP access in CNS), and I can just choose to pay for Economy X or extra legroom on QF, knowing it was the opportunity cost forgone by not spending the total $9.6k with VA just to maintain access to Economy X.
Glad that Fly Ahead remains for Gold.