Diminishing returns.
Slow/stun/root resist or freedom buff that stacks for a certain amount of time after being disabled. The fact you don’t have this is pretty insane imo.
Each stun/root/slow/etc. adds a stack of freedom for 5s, each new stack before expiry refreshes that 5s cooldown. Would obviously need balance, but something like this is badly needed and would make melee a lot more viable, but also would make people think a bit harder about using their abilities properly.
In OPR it feels like my entire server is fire staff, IG, just hucking fireballs and showers.