Estates don't affect Morale, Production etc. any more, but Estate Efficiency is used for Tax Collection. Say if your Region collects 200 gold, and your 50% Estate has an efficiency of 80%, you'd get 200 * 0.5 (Estate Size) * 0.8 (Estate Efficiency) = 80 gold from it. Not sure if that's the actual formula but that's the idea behind it. Of course, smaller Estates may have higher efficiency and increase total tax income, they might need to be so small that it only offers a too small income for the Knight in question. It also requires you to find Knights to fill all those Estates in the first place (All non-filled Estates have an efficiency of 50% like Wildlands). The rule of thumb is: Max income for the Lord is taking one biggest size Estate and leaving the rest Wildlands with no Knights. Max Income for the Region is having 100% efficiency Estates taken by Knights, though this tends to decrease personal income depending on the Lord's Share (Except when this is at 50% in your case). Efficiency depends on Region Type and Population, so I suggest experimenting what gives you the best setup.
But due the above, you'd usually see something in between, like your current Estate Setup, that provides decent Efficiency and decent Tax Income to all Knights, without making individual shares too low or requiring too many Knights per region (Though keep in mind, that if you can, having more Knights can give you more power within a Realm, at least indirectly!). A Lord's Share of 50% is pretty high though, and may not entice Knights to take an Estate in your region as they are forced to hand over half of their income to you. Other regions probably will give them a better deal!