I have a couple ideas;
1) I think the first 10 draft picks should be "lotterized" - same system as we have now, but by having a lottery for more picks that gives the teams that just barely don't make the playoffs the ability to land a decent pick in the draft. Currently, the team that finishes 17th overall, being the best of the non-playoff teams, is the team that gets shafted the hardest. Give them 10 lotteries as a chance to improve that position. As a team wins a pick via lottery, the percentages continue to rise for the other teams by virtue of less teams left in the lottery.
2) Equal percentage lottery for all non-playoff teams. You can only go down one spot, but every non-playoff team has an equal chance at the #1 pick.