So, yeah. At this point, Ukraine's demands should be:

1. Russia withdraws from all of Ukraine, including Luhansk, Donbas, and Crimea.

2. Russia publicly and irrevocably repudiates any and all claims they may have to any and all territory outside of Russia, including but not limited to Ukranian territory; all claims, whatever their origin, be it historical, ethnic, linguistic, or imaginary, all claims, past, present, or future. They must repudiate these claims across all media, both without and within Russia. The list of claims repudiated should be exhaustive, but not exclusive.

And the moment Russia repudiates said claims and is no longer in Ukraine, Ukraine is in NATO. No approval process that Russia could jack-fuck by launching another sneak attack. Just "in, immediately." Any further attacks will trigger Article 5.

They should probably forget about any reparations or getting their hands on any war criminals. The only way they could press those claims would be when the blue and yellow flag flies over Moscow, and nukes will fly before that happens, even if NATO did just basically throw the floodgates open wide and turn all of Ukraine into an arms depot. While that sucks, sometimes you have to settle for the victory you can get, not the one you want; also, Putin, at least, is a dead man either way, as a dictator can't come back from getting his cock knocked in like this in a fight he started. (Or, indeed, one he didn't.) Someone will off him in a year or two at the most.

Also, they can quietly continue their forensic investigations. Sooner or later, some of the crims they want will travel, and then they can have them grabbed and dragged to the Hague.