If you are flying TPAC, you'd still have lounge access in Asia and the US as a Gold. It's only on purely US domestic itin's where you would no longer have it. This doesn't seem to be that big of a loss.
I certainly realize that for GM+ you are all STE+ now, but the loss is lounge access when traveling domestically in Asia at the hub airports (within Japan, Korea for instance), flying a non ST carrier internationally worldwide, and also flying domestically in the US.
For US based flyers of course it is no issue as with all recent devaluations. My point is for Asia based flyers it is yet another stab in the back from DL saying "we don't want you."