I think this is the point where I disagree with you, and accepting or rejecting this premise leads to very different solutions. Now, it's true that this year there are what I would consider to be 8 bad teams (the Knicks don't really count, because they were clearly better than the others before Porzingis went down) and maybe there's not too big of a talent gap between them. But this year is unusual in terms of bad teams. There are probably going to be 9 teams with under 30 wins, which will tie a record for the most teams under 30 wins in a full season since the league went to 30 teams - the average in that time is 6.15. Furthermore, the gap between teams #1-#9 in the lottery will be at most 11 wins, and likely 8 or 9. Since 1990, the smallest gap between #1-#9 in the lottery is 11 wins, and the average is 17.7, going as high as 25. So this year there actually is a lot of "parity" at the bottom of the league, but usually that is not the case.
So, if I accepted your premise (the bottom 10 teams in the league are about equally bad most years) then I'd say setting the lotto odds equal for all those teams would be reasonable. But when the gap between the best and worst teams in that range averages nearly 20 games, well, if a lottery is the solution you pick then a weighted lottery seems appropriate to me.