Are you setting your global production slider too aggressively? Coercion has quite a big unhappiness penalty now. Having said that I generally only find morale to be an issue very early game, once every planet has a happiness starbase, and every planet 1-2 happiness buildings you can support huge populations without any issues arising with happiness even with a 10-15% penalty for some coercion while you rush towards a tech victory or whatever.

x = total Morale for the planet.  Approval = Morale / Population.  If you hover your mouse over the Approval rating for your planet, you can see this.

The higher your pop, the more Morale you need to produce to keep the Yor "happy".  So you need approval buildings and/or starbase modules.  For my Yor, I always get Supportive Population and then usually try to build a malevolent Intimidation Center adjacent to an Entertainment Center.  When pop gets even higher, then another Entertainment Center and especially the Promethion Pleasure Park help a lot.