Hey,
I don't know which item I should replace to increase my DPS/EHP.
I think the amulet is the worst item, but I try to craft a better one.

Or would you suggest that I should try to get more hatred or discipline (reg) first?!

Some other notes:
-An increasement of +1% CC means +2800dps, +10%CD means +2500dps, +1%AS means 1000,+10Dex means 700dps.

-I've got a budget of 50million.
I would be very glad if someone could help me with a good idea.

Hmm.. your amulet actually looks fairly nice to me. Over 200 dex, maximum CC, decent CD, & the reduced damage from ranged attack is actually quite nice for EHP, especially since DHs are ranged heroes.

Maybe switch out your Natalya's Reflection for one with either CC or CD? Or your Inna's Vast Expanse for a Natalya's Cloak? Since the set bonus for 2-piece Inna's is the same as 3-piece Natalya's (i.e., +130 dex), you're not losing too much in that sense, but might be able to get a good bonus item on the cloak, such as max discipline, hatred regeneration, &/or bonus to a particular DH skill...

Also, Dead Man's Legacy quivers are fairly cheap right now. I'm sure you can get one with maximum attack speed (you're at 17% now) & maximum CC (you're at 9.5% now), and probably even maximum hatred regeneration for only a couple million gold.

Ditto for double-socketed manticores; trade your current one in for one that has at least 95% CD (you're at 82% now). They're not too expensive on the AH right now either.

Switch out your gloves too maybe. Do a search for a rare pair with maximum CC (10%) and either a variable attack speed or CD (i.e., leave those fields blank), & see what prices come up.

Just my two cents. Hope this helps. :-)

EDIT: Forgot to mention--if you have a budget of 50 million to spend, might want to consider spending some of that cash on upgrading the amethyst in your helm from a +14% life gem to a +18% life one. That would definitely provide a good small boost to your EHP...! :-)