Just got done playing some Nemesis games.
Here's my advice.
First off, EVERY champion is good.
They just aren't all on the same level.
What do I mean?
Well there are alot of Urgots going around in nemesis, and people haven't figured it out yet.
Urgot MAY BE a bad ADC, but he is STILL an adc.
Why give the enemy team an ADC?
(Side note: If you DO get urgot, build him ADC, not some crazy build. You got a huge advantage handed to you, don't waste it.)
What you SHOULD be doing in Nemesis Draft is putting together a weak TEAM.
Not "The worst Champs in the game."
Give them a bad TEAM.
All squishy supports? OK
All melee tanks? OK
No engage comps? OK
No CC comps? OK
No junglers? OK
You see how this works?
By picking their team, you get to create an advantage for your team.
You get to choose what the enemy team will be bad at.
Then you exploit it.
The challenge in this game mode is that it forces players to play into weaknesses, not strengths.
Itemization is extremely important.
You just might have to ADC Janna, do you know what you should be building to do that?
Also, an observation.
I am AMAZED at some of the champs that people think are "Bad".
Sejuani, Gragas and Nautilus are not bad.
Those champions will ruin your day if they are played correctly.
Also, for whatever reason you guys are doing it, stop giving out meta teams.
You may think Nunu is a bad jungle, and for whatever reason that MIGHT be a valid arguement.
BUT HE IS STILL A JUNGLER.
If you want them to have a bad jungler, give them all supports.
Also, if you are stuck on what to give the enemy, then give them a mechanically complex champion.
Elise is a good example here.
Elise isn't bad, but if you give her to someone that has no idea what she does, they will spam two abilities max the entire game and play terrible.
EDIT: Also, FYI, AP Rammus is fun as hell.