With the introduction of Shadows of Mirkwood, crowd control effects (CC) in the 'moors have reduced effectiveness with every application.

Per Frelorn in http://forums.lotro.com/showthread.php?p=4107893#post4107893

Changes to CC Diminishing Returns
All crowd control effects (fears, roots, stuns, and dazes) are now on the same application counter. This means that for purposes of diminishing returns in PvMP (and in PvMP ONLY), each application of any crowd control effect is counted against the duration of the type of crowd control.

Update Vol III Bk1:  CJ's are now affected by dimishing returns on their own separate counter.

For reference, the duration tables of each crowd control effect vs. application counter are below:

Roots/Dazes

• First Application = 50% of the root/daze duration
• Second Application = 25% of the root/daze duration
• Third - Ninth Application = 5% of the root/daze duration
• After the Tenth Application, the root/daze will no longer affect the target

Stuns

• First Application = 100% of the stun's duration
• Second Application = 50% of the stun's duration
• Third Application = 25% of the stun's duration
• Fourth - Ninth Application = 1 second stun duration
• After the Tenth Application, the stun will no longer affect the target.

Fears (please note that this applies only to crowd control fears - this does not apply to debuffs with resistance type: fear)

• First Application = 100% of the fear's duration
• Second Application = 50% of the fear's duration
• Third Application = 25% of the fear's duration
• Fourth - Ninth Application = 1 second fear duration
• After the Tenth Application, the fear will no longer affect the target

Conjunctions

• First Application = 100% of the conjunction stun's duration
• Second Application = 75% of the conjunction stun's duration
• Third Application = 50% of the conjunction stun's duration
• Fourth Application = 25% of the conjunction stun's duration
• Fifth - Ninth Application = 1 second conjunction stun duration
• After the Tenth Application, the conjunction stun will no longer affect the target

For an example with this application counter change:

You are hit with a daze effect in PvMP. It is counted as the first application of a CC effect, and the daze effect duration is 50%. After it wears off, you are then hit with a stun. It is counted as the second application of a CC effect, and the stun effect duration is 50%. After it wears off, you are hit with a root. It is counted as the third application of a CC effect, and the root effect duration is 5%. After it wears off, you are hit with a fear. It is counted as the fourth application of a CC effect, and the fear effect duration is 1 second.

Please note that the diminishing returns application counter is not permanent - if you are not hit with any crowd control effects for 45 seconds, the application counter will reset.