Maybe not the easiest fix, but relegations would be the coolest. But practical changes like raising the minimum salary, letting players get to arbitration and free agency earlier also make sense (for the players). If you're not Bryce Harper, you get paid shit through pre-arb and arb, then then might get ignored for another guy getting paid shit when you finally hit FA. Maybe also a minimum salary floor, or requiring that all revenue sharing be re-invested in scouting, player development, or player acquisition (no personal debt, off-field expenses).