We're more or less in the most balanced meta I think we've ever honestly had. Supports can peel for ADCs reasonably well, buff the team well, and heal well.
Tanks are reasonably tanky for once.
Bruisers/Fighters are capable of killing ADC's, without being too overbearing, allowing personal skill and teamwork to determine the outcome of the fights.
Assassins aren't faceroll instant win anymore, supports will peel them off and keep the ADC healthy without proper coordination in place.
Mages, despite being a bit lackluster in build variations, are still strong.
ADC's are extremely powerful, but very reliant on skill, proper positioning, and teamwork in order to win. They can 1v1 assassins, but only if they play it right. The same goes for the assassins against them, it's a double edged sword for both sides. I'd like to see a bit more variation available for ADC's in build options as well. We only really got one set up per 'type' of ADC, or for each ADC in question.
Example for ADC build rigidity, you build big AD item (BF Sword, Pick, Double Longswords if you're poor), grab attackspeed berserkers or zeal, berserkers if getting rekt by Thresh/Blitz/Morg, or getting camped, and then go into IE / ER. IE on say Cait, ER on Xayah. Then you typically rush out attackspeed crit item, and on most ADC's of this category, take IE/ER depending on what you didn't take after the attackspeed crit item. On Cait you take IE - > Shiv/RFC - > RFC/Shiv. No real variation available for optimization of damage. Hurricane would be good but you won't live long enough to benefit off the increased availability of headshots (teamfights are very short), and building only Hurricane + RFC is bad b/c of RFC's improved passive, you generally want Shiv + RFC for massively improved damage with a headshot to chunk people out to half before a fight.
-Obviously there are attackspeed ADC's like Kog that are the exception; and some champions have different optimization paths, like Xayah typically builds with a focus on attackspeed to gain massive increased damage via her E's return damage. While builds from Champ to Champ may vary, consistent builds on the characters themselves do not.
AP it's kinda similar, rush out a Morello every single AP champ minus non-mana users have to.
For non-mana users it typically looks something like Hextech gunblade/lichbane, or liandrys/rylais. With a Rabbadons/Voidstaff included somewhere in the build as well.
Game doesn't revolve around one role, all roles are equally valuable. A good tank can frontline to soak up tons of damage, hard engage or prevent the enemy from doing so, and are extremely annoying to deal with. Traditional healing supports are great at sustaining the team, peeling, and using CC to catch people out. Mages tend to have greater range, good waveclear, and are comparable to ADC's in damage output. Fighters/Bruisers can slaughter tanks, and if they are reasonably good, can defeat any other role. Assassins can wipe out squishies in the blink of an eye. And marksman are great at siege, teamfight well, and maintain high power due to their innate weakness of being vulnerable to just about anything.