I think Nemesis has the potential for some of the most entertaining plays. (very brief story)

I think this kind of mode is a true test of summoner ability, which is of being out of your element in a less-than-ideal situation, and needing to improvise on the spot with what you've been given by the other team. It reminds me of Arena in Hearthstone, where you just get random cards, making things pretty much even because you can't organize anything ahead of time, and many people say that's a test of how good you are at that game because you don't pay to win at all.

Nemesis has a similar feel to it, I think.

It's because it requires creativity, as well as risk. It requires actual intelligence as opposed to practicing a certain champion repeatedly. It requires more teamwork than a standard Rift game because you're probably not going to be handed your usual Katarina carrier, or anyone else known to be even remotely useful. At least, not to them.

It's also because the people opposite you who are picking for you seem to often hope that you simply are bad with that particular champion, but this isn't always the case, thus the risk in picking "lesser" champions, or high-difficulty champions. Hence, you see a lot of picks for champs like Orianna, Singed, or anyone who would be very difficult for a first-timer.

The fun part is obvious. Since you can trade with your whole team, there's a huge risk in doing that, and that made a game in which I got Orianna--someone I'm certainly familiar with--very fun. That initial chat between the teams went like this (I was using Winter Wonder)

Shen(All): do you know how to play ori Orianna(All): yes Shen(All): darn

I wasn't alone in this. We had a guy familiar with Taric, too, who tore up when they handed him that champ.

BONUS NOTE This is a very toxic mode. Holy Smite do people go nuts in this, as if the point isn't to be in a less-than-ideal situation to begin with. I'll give a perfect example.

My second time in the mode, we lost. Horribly. I was the jungler (as Yorick), and I did secure three dragon stacks and stole buffs constantly, but all three lanes were being disastrously decimated and there was seriously nothing I could do that early to save all three lanes at the same time (laners don't seem to realize this fact that there's one of us, and only one, and we can help exactly one lane at a time). But without reciting the jungler's griefs all over again, it was amusing that I was reported for "assisting enemy team" (uh, okay), but received three honorable opponent honors (which weren't for that, I assure you, but this team was going nuts in allchat to each other, and I was seemingly the only one not screaming).

Anyway, while the dodging and rather insane amounts of toxicity are there (not that I didn't expect it), I'm having a great deal of fun with it because I like the challenge.

It's also nice to see a "big play" with someone besides goddamned Lee Sin or Katarina, honestly.