This trade basically boils down to Porzingis for Smith + 2 future #1 draft picks. The rest is fluff and cap matching.
Dallas wins trade of Porzingis stays healthy and he and Doncic go on a 10 year run as reincarnation of Nash and Nowicki.
Knicks win trade if they land some top free agents for next year - say Durant and Irving, and the draft picks work out - both the future ones from this trade - and next year's top 5 pick.
The poster above really hits on the issue with the Knicks (and some other teams) in how poorly they communicate with their $20 million employees). The organisation brings in guys like Noah, Rose, Kanter (Burke, Hardaway) and soon to be Ntilikina and then doesn't communicate to them about their role, so they only hear about their situation form the media. If I'm managing a McDonald's, I'll at least communicate to employees and be aware that morale is important. These guys are expensive employees and deserve to know what's happening. It does no good to treat them poorly, as with guaranteed contracts, you still have to pay them $millions anyway. Porzingis issues with management were about communication, and how players were treated - not about future basketball strategy.
So now Porzingis goes to a team with a healthy organisation, and experience with international players.
The Knicks will probably screw it up with the wrong free agents, bad draft choices and dysfunctional communication.
One side note - Burke and Hardaway are both only 26 and actually can fit in well in Dallas, if Mavs are willing to pay them and keep them.