MSTU: Observations on Top Lane Tanks
Let's look at the initial performance of a few of the tanky titans of top after the big midseason update. All data is taken from LoLalytics.
FI: Most common first item MSTU: Mid Season Tank Update
: Stagnating. His performance looks not to have been impacted majorly. FI
: Performace drop (about 49.5% to 48%). FI
: Drop in performance from about 50% to 48%. FI
: Major decrease from 52% to 49%. FI
: Stagnating. Interestingly, massively increased pick rate did not affect winrate too much. FI
: Performance reduction from ~48% to about ~46%. FI
: Drop in performance, from 49% to 47% and falling. FI
: Decrease in winrate, ~50% to ~48.5%. FI
: Reduced performance, from about 52% to 49%. FI
: Massive drop in performance, Riot really misjudged the power level of his rework. Winrate from about 52% to sub-40%!! FI 
I am starting to see a pattern here: All tanks that were using Sunfire Cape as a first item are exhibiting a significant drop in their performance post-midseason.
Given the nerf to Sunfire and Bami's Cinder, that was to be expected. But what it really shows is, imo, how much Sunfire Cape was responsible for the strength of the top lane tanks in the last year (ever since its buffs in 6.1 and 6.3, top lane tanks were a staple of the meta).
What I am interested in is how tank builds and the top lane meta will evolve in the upcoming weeks. Will tanks in general or specific picks find ways to overcome the nerfs to Sunfire Cape? For instance, I can see Sion going for some AD early or Poppy taking up an early Sheen or Tiamat to melee it out with her counterparts. And were will competitive go with this? Will these changes herald the return of the top lane bruiser? Will Irelia have to be nerfed again? Finally, how is Riot going to save Zac? Will they revert the duration nerf to Elastic Slingshot's CC effect (I hope)? How will they make Q more fluid and less annoying to use?
more often as
&
.
You know, the core items for the role. (>_>)
and
are much better choices. Knight's Vow especially due to it giving your ADC PD's passive but slightly better. It's very undervalued but huge. Ardent you your ADC is AA based or you've got a Kayle.

If you skip Sunfire, you litterally have no waveclear
I've killed a Lux on my own with an E over a wall, in about 5 hits.
That being said I usually upgrade Tiamat last item anyway, since Tiamat is a lot smoother for me.