In your opinion who in each division is the toughest matchup for the current champion of that division? The ones without a question mark are the ones I think many/most people would agree with.
Werdum - Overeem? Stipe?
Cormier - Jones
Rockhold - Romero? Vitor still?
Lawler - Maia?
RDA - Khabib
Conor - Frankie
Cruz - TJ still? Someone else?
MM - Cejudo? No one (lol)?
Tate - Ronda
Jedrzejcyzk - Gadelha?
Werdum - Cain Velasquez is a beast both on the feet and on the ground, and I think he's able to give Fabricio a lot of trouble. Looking forward to the rematch.
Cormier - Jones, no doubt.
Rockhold - Either Souza, who could potentially outgrapple him, or a dangerous striker like Vitor, who could KTFO him again xD, though Rockhold's stand-up has massively improved, and idk if Vitor could repeat his success.
Lawler - GSP if he ever comes back

Stephen Thompson could be very dangerous for him as well.
RDA - One of my favorite fighters, don't think there's anyone that could beat him, except Khabib, though RDA will have learned from their first fight.
Conor - Most definitely Chad Mendes. He was able to hold his own on the feet, and brutally mauled him on the ground. Looking forward to a fight when both have a full training camp.
Cruz - another of my favorites. TJ did present some trouble, but I think Cruz would beat him easily in a rematch. A Barao fight would be interesting, a good low-kicker could neutralize his footwork.
Mighty Mouse - no idea, maybe Dodson? Cejudo looks dangerous too...
Tate - definitely Ronda, and Holm if she works on her defensive wrestling and BJJ. That's pretty much the top trio of women's BW. Don't think the others are anywhere near them, and they're all dangerous to one another.
Jedrejczyk - don't know much about strawweight, but given her excellent striking, should be the best SW wrestler, whoever that is xD think Joanna went through all of them though.