[4e] Warlock Implement vs. Saves

[drawingfreak]

I've been trying to locate an implement that would allow one of my players to lower the chances of enemies to make their saves. He is playing a Warlock of the Dark Pact and with his 1st Level Daily spell (Contagion), he wants to be able to infect as many as possible.

I would like your opinion on my Implement design. I'm going for something Level 4-6 with a minor effect on enemy saving throws.

{table]Damnation Rod +1 | Level X
Enhancement: | +1 to attack and damage rolls
Critical: | none[/table]

With either:

Property: Enemies under your Warlock's Curse take a -1 to all saving throws.

OR

Power (Daily): Immediate Interrupt. Use this power when an enemy attempts a saving throw. They take a -2 to the roll.

[Shadow_Elf]

I've been trying to locate an implement that would allow one of my players to lower the chances of enemies to make their saves. He is playing a Warlock of the Dark Pact and with his 1st Level Daily spell (Contagion), he wants to be able to infect as many as possible.

I would like your opinion on my Implement design. I'm going for something Level 4-6 with a minor effect on enemy saving throws.

{table]Damnation Rod +1 | Level X
Enhancement: | +1 to attack and damage rolls
Critical: | none[/table]

With either:

Property: Enemies under your Warlock's Curse take a -1 to all saving throws.

OR

Power (Daily): Immediate Interrupt. Use this power when an enemy attempts a saving throw. They take a -2 to the roll.

If you make the first one "Enemies under your Warlock's Curse take a -1 penalty to all saving throws against effects imposed by this rod", then I think it'd be balanced as a level 4 or 5 item. Oh, and +1d6 critical per plus.