I have a different point of view on this.
If we look at the cup, league and CL draws, the teams are drawn in such a way that anyone can be the winner.
Sure, you may be at a disadvantage sometimes, but you can still win.
If you have a 4* team, you get drawn against other 4*/5* teams in these competitions (there are anomalies of course)
You wont be paired against a team that is 2* greater than yours in cup or CL.

So, that doesnt justify a tanking season.
There should be a 20% uniform deduction for all teams, irrespective of position in league.