Give me your top 3 strongest and weakest champs in TFT
In general.
Top 3 I'd say; Best
- Shyvana
- Cho'Gath
- Zed
Worst
- Twisted Fate
- Rek'Sai
- Ahri
In general.
Top 3 I'd say; Best
Worst
In what regard, like on their own? With or without items?
Best?
1 Swain 2 Karthus 3 Sejunai
Worst
1 Rek Sai 2 Braum 3 Fiora
Best -Chogath -kenen -Draven
Worse -Elise -Rek sai -Katarina
Best:

Worst:

Best:

Worst:

Best. Swain Draven Lucian Veigar
Worst. Graves/TF Elise Rek'Sai
Best:

Worst:

cant say any are particularly stronger or weaker than the others. But I can give you a subjective list of favorites and hated units?
Favorites: Twisted fate, lucian, kindred. Tf is good random ass fun, lucian can do silly things with gunslinger up and items and kindred is a fun combo breaker
Hated: Kha, cho,reksai(BONUS:Kassadin) Always at least two or 3 people trying to force the void bonus as though they're the only 3 units in the game. Boring to see all the time.
Best : Kennen Cho Pyke (All can plug and play into any comp)
Worst: Fiora Morde Graves (Literal "tag" champions to make something else more viable)
Only correct answer
Best
Cho Kennen Karthus
Worst
Elise Graves Vayne
Favorite:

3)
Least Favorite:
2)
/ 
Favorite:

Least Favorite:

In isolation? With their origin/class in mind? With items? On lvl 2/3? Makes alot of difference for many of them...
Overall though: best: Karthus Cho Draven
Worst: Reksai WW Graves
Though fiora, kah, elis, morde and darius(exept for early) are quite bad aswell.
I think it's unfair to compare 2 costs with 5 costs as you did in your OP, of course the 5 costs are better.
Best: Khazix (1 cost, solid unit that is reliable early game and has void synergies) Lulu (2 cost, if you give her a mana item, she'll just ult nonstop), honorable mention Lucian (the dash can make some rangers like Ashe miss their ult) Volibear (3 cost, a carry that's also tanky? sign me up) Draven (4 cost, insane damage output) Kayle (5 cost, it's the only 5 cost I need because I main 6 nobles)
Worst: Mordekaiser (1 cost, practically useless for anything except 6 knights) Ahri (2 cost, practically useless, can't think of a comp that could use an Ahri), honorable mention TF (more like a 1 cost unit) Ashe (3 cost, not terrible but should rlly be a 2 cost unit) Kindred (4 cost, basically Shen except more expensive) Yasuo (5 cost, because he's only good on his own due to his ability, but he gets eaten up like paper because he has no support from his team), honorable mention Anivia (too squishy, almost never gets to ult) and Karthus (also too squishy, almost never gets to ult due to the long channel)
Several people putting Rek Sai in worst are pretty insane [slayer-jinx-unamused]
Either that or they are used to coming in the bottom 4 because they can't determine how strong a champion is even though Rek Sai hasn't been garbage for a while now.
Best 3:
Worst 3:
Best should be obvious. Fits a lot of comps, generally doesn't lose power over the tenure of a game.
Worst:
Kassadin is by far the weakest disrupting front line in the game. Although he burns mana, other items apply similar or overriding effects. Only affects one, and even if you try to build him immortal, he can die as a 3 star. He fits a lot of comps, but has the worst weathering of those comps per team.
Vayne: Generally only fits in with Ranger (weak compared to other sharpshooter types), or Noble, Slot filler. Only has an impact in drawn out fights with Warmog's users with high HP.
Twisted Fate: Basically plays like a Tristana that doesn't have Gunslinger. Skill rarely gets off more than once/twice, and generally doesn't have the impact you're looking for, and has a charge up to use which by default makes it an inferior skill to things that end fights quickly.
Strongest: Draven, Jinx, level 2 kayle with 2 spears rageblade (double perma ult with like .2 seconds downtime) Weakest: Morde, Blitzcrank (easy to position agaisnt cuz theres only 2 spots blitz can hook), Lissandra