Here are the counts of the most strongest champion on solo que for each lane.Starting in the top lane, of which i think is the stongest champion now is Wukong, the black clever changes did it well on rellying on interget thru the teleport play, wukong truly shines thru. His ultimate combines with his stealth ability does great rome and on team fight. His laning phase also really strong as he can gank effectively it has good trading and disengage. It also scales perfectly with black clever to give him the thankyness and to dominate on team fight.
Next is the strongest jungler, that i believe is Vi. Vi succeed a lot due to the fact that she had a dynamically play style, she can be ether thank or do a bit of damage to the enemy. Either way she still strong due to her play making potential, the ganks are great and team fight are solid as well. She does well on kiting and do stuff as a jungler would do. Not to mantion that her mechanic are easy and to do well with.
On the mid lane, Ahri. Ahri is a very storng mid lanner as she is strong to kite the enemy team to engage and disengage due to her strong poke and all in ability. Shes also good in team fight, by using her charm to lure one of the enemy out of the team fight. As she reach level 6, it is mostly impossible to gank her so that to have more power to push up lane.
Next is the strongest AD carry, i would say Ashe. Even with the minor nurffing that been done, she is still a strong adc. Manly due to her raw utility that she brings as a champion. Ashes ultimate is by creating a great tool in the game for starting fight, and doing so you could win a lot of fight and get a lot of free kills just by ultimate someones out of position. Tho she still venerable on team fight, try not to get into position where the enemy could jump on you.
And Last but not lest, the strongest support who i see is as Janna.
When ever against a thank, Janna would probably have great essential against them. Thanks really get countered by kiting, and Janna kites thanks better thank other support. She plays a great option for a support and fairly easy to play with.