Couple of caveats here- the revenue dropping is in mobile spending. Due to the webstore most will spend there due to the benefits (however small) players will receive by doing so.
Secondly alongside that assumption I'm sure CG have metrics which point them to what works to increase spending. None of your ideas are actually ways to increase player spending, just ways to balance it less towards spenders which will not increase spending as obviously Whales need a power / reward disparity over those who don't spend.
100% agree about TW, simply increasing the rewards compared to the amount of effort needed would help. As an end game guild member we just don't bother unless its an easy win.