Preferred anti-tank, botrk or dominiks?
Playing Yasuo, ult everything? Regardless of situation ( low hp, heavy cc opponents, outnumbered) my team and I seem to disagree on when yas should ult
Essence Reaver viable yet? On who?
Team losing lane and/or feeding, abandon your lane to help them or secure a tower kill?
1- Fully dependent on your champion which one you get. Sometimes you get both. 2- Don't ult everything. As with all champions, you need to learn when to do what to win, you can't just press buttons. 3- Highly viable, on a ton of marksmen. Mostly ability based ones, like Lucian or Jhin. Not Ez though, as he doesn't build crit. 4- Same as with the second question, you have to know that yourself. Roaming can help, but sometimes it's just not worth it. Sometimes you just won't get the kill and will instead lose your own tower.
I tend to see more Dominiks and it seems to work out
Don't ult everything, you should learn what you can and can't fight as Yasuo over time and you'll get a better idea of when to ult or not.
Essence Reaver is viable on most marksmen
Depends on the situation, if you leaving lane will cause your lane opponent to get your tower or an objective, it's probably not the best idea. Coordinated ganks with the jungler might be able to set them back on track. Also make sure you know whether or not you can get the tower. If you head down to another lane and don't end up doing anything, you missed out on a lot of CS that your opponent just got.
Dominik's, Youmou's, Black Cleaver
Only ult if your team can followup, OR you can kill more than one person off it.
It's more viable than most AD items. It's fantastic on Sivir (Essence Reaver, CD Boots, Infinity Edge), Corki (Triforce, Stattik Shiv, Essence Reaver), and ADC Varus.
Push the lane then gank/TP to another lane and get an objective/kills to even out the lane.
Thank you both specifically on number two That was sprcific to a situation where my team (heavy in knock ups) wanted me to ult every time it presented itself. They were raging because I refused to dive in on a full hp tank heavy team
This is should only be bought IF the enemy is stacking armor AND has more health than u. 
can be bought in way more situations:
?
Do you want an item that has an active which gives you self-peel?
Are you facing high hp enemies?Get this item if you answered "yes" to at least two of the questions above. Botrk isn't meant to be compared to dominik's. League is about optimizing your itemization so buying the right item in each individual situation. Hope this information helps.
3.Essence reaver is viable mostly on adcs which i will list as follows: 
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( this list has been compiled based on common trends on builds i've seen from challenger elo players)
