My biggest issue with the Daleks in the Dalek Mod is that instead of adding new ways to fight them, they get just nerfed. This is the best way to change this.

1 - GENERAL CHANGES.

-10-12 damage instead of the current 6.

-Knockback reduction.

-50% chance for the shot to pierce true the target.

-10 armor (this one I think is already coming in U64).

-More aggressive AI.

-Improved aim.

-Explosion resistance. Because Special Weapons Dalek keep killing other Daleks.

2 - EACH ERA HAS A DIFFERENT DALEK.

60s DALEKS.

-30hp.

-25% knockback reduction.

-Slowest attack rate.

-Least explosion resistance.

70s/80s DALEKS.

-40hp.

-50% knockback reduction.

-Attack rate faster than 60s Daleks.

-Better explosion resistance than 60s Daleks.

MODERN DALEKS.

-I'm fine with their health right now.

-100% knockback reduction.

-Fastest attack rate.

-Best explosion resistance.

-They spawn with 10hp of Absorbtion.

-When fighting there is a chance they fire a burst, a number of repeated attacks. Their aim will be significantly worse while doing this. After the burst ends the Dalek will have a significant cooldown before attacking again.

-They can also hoover.

NETHER DALEKS.

-Like 70s Daleks but instead of their Gunstick they use a flamethrower.

ENDER DALEKS.

-Like 70s Daleks but they also have 10hp of Absorbtion and can hoover. They can also teleport if the player gets too close or rarely to dodge incoming projectiles.

STEAMPUNK DALEKS.

-Like 70s Daleks but they have the "claw" arm, meaning that they can cut through iron doors and burn down wooden doors. (?)They can shoot a spray of steam, giving Blindness to the player.

3 - MISCELLANEOUS CHANGES.

-"Important" Daleks such as Commanders or Supreme should have 10 more hp than their normal counterparts and shouldn't despawn.

-Time War Commanders should be an actual mob.

-Killing a Dalek in a Hoverbout is easier than killing a Dalek on its own due to the Hoverbout's ridiculously low health. Hoverbouts should have 100hp.

-I remember that in Dalek Mod Legacy, New Paradigm Daleks had special abilities; for example Scientist Daleks could turn invisible. If elaborated a bit, this could be a great way to make Dalek fights more unique.

-Special Weapon Daleks should do smaller explosions.

-A few changes to the Dalek Saucer. Instead of having a Time War Dalek spawner, a Drone and a Dalek Sec one there should be two Time War Dalek spawners and one Drone Dalek spawner plus the aforementioned Time War Commander. Also a few Hoverbouts should spawn around the Saucer to make entering it more of a challenge. Due to these changes the quality of the Saucers' loot should increase.

4 - NEW WAYS TO FIGHT THEM.

Now that the Daleks have been buffed, there should be new ways to fight them.

-Metalert and Dalekanium armor should have Laser Protection. Also Metalert armor should have diamond-level Armor Toughness.

-Metalert and Dalekanium swords should deal 1.5x damage to Daleks.

-Hitting the Dalek's eyestalk should ignore all armor and deal 1.5x damage.

-Anti-Dalek Neutron Exterminators should be added. They would normally deal 8 damage like other Laser guns, but do twice the damage to Daleks.

-In Parting of the Ways and in Stolen Earth, Jack Harkness uses a gun to kill a Dalek. I don't know the name but I know a way to implement it. It would shoot a ray, if the ray stays in contact with the Dalek for long enough (2 seconds or so), the Dalek would explode similarly to what happens with Nitro-9. After this it would have a 5 seconds cooldown. It should be expensive to craft to keep things balanced and encourage the use of Nitro-9.

Those things require an end game lever progression, so it would be better to make Dalek spwning in the Overworld minimal, and mostly deep underground.

Dalek spawn rate and stats could change depending on the game difficulty.

That's it. I hope some of those suggestions are helpful.

Nice ideas :)