Well I probably get in trouble for saying this but as i see it a map reset is imminent and I am ok with it.
All the ocean areas will be broken down into multiple biome types, frozen. cold, warm , mild and multiple variations of them. Along with 48 desperate ruin types, fish only in certain water types, shipwrecks, 5 different trident types. I know all the map hasn't been explored and these area could be updated but with all the issues with rain off, renaming items, water mechanics breaking most machines, mansion mechanics plus all the update features it makes the most sense to start fresh to address as many of these as possible.
I am sure ill get in trouble for being honest and accused of map reset hysteria but that is how I see it.
Do i want to lose my wealth and all I have built not really.
Do i want to have a messed up map and have to deal with machines needing redesigned? no
If i have to choose from those 2 evils i choose map reset to fix mansions, all oceans equal and hopefully fixing phantom and rain issues.
Well that is my 2 cents worth and as far as I am concerned this is all 1.13 update related