And on a sidenote:

Whirlpool transactions are valid Bitcoin transactions with fully paid for fees. It doesn't make any situation 'horribly worse'. 

Toxic change is spendable, but it comes with privacy implications. 
Swaps or their future multi party Tx0 transactions will fix that as well.  

 The tx0 premix transaction makes the block space consumption and privacy horribly worse for Whirlpool compared to skipping the premix and coinjoining directly:

https://image.nostr.build/14026e01cbbd0981d24e2b4866265f026b92bc584d9e2dc16acf1d641a4b69ef.jpg#m=image%2Fjpeg&dim=1544x1491&blurhash=%7C8SF%40R%25M%7EqMy%25hgLogt8wgtRM_D%25xvR%24xv-qV%40oNxbbakCoLR*aejZWUj%5Bxuj%5D%25MWURQWANFoMW-%3FcMxIU%25gNFWExuRjRkM%7BX7xbnQR%2BbEWBX7spf%2CxakBIonjazWBxHNssEt7kCRPtQV%5BM%7BxuRjIUof%25LRkV%40oeWCWAog&x=3226e49be19cf5640fddfd6ca3bccf5b980d5202c66abdcbe16ee69572319df1