I just looked at this. If you could only have a top 3 pick once every five years, these teams would not be eligible this year:
TWolves, Lakers, Sixers, Cavs, Bucks, Magic, Wizards, Pelicans, Hornets, Jazz.
In other words, the only teams eligible to receive a top three pick in this draft would be (as of current standings): Detroit, Phoenix, Toronto, Sacramento, Boston. And obviously, the team with the highest odds of getting the first pick would be the Suns. Of those teams, I can only see Phoenix and Sacramento deliberately tanking. It would depend on how the lottery is weighted.
Just goes to show how bad some teams are, repeatedly.
It could be interesting if the restriction is based on the team picking, not whose pick it originally belonged to. It might encourage teams that already picked in the top three to trade the pick to a team that has not, since the pick would be more valuable to them. Thus, it would make it easier for bad teams to get quality veteran talent.