I am not talking about Zerg Hydra being too good, I’m talking about Protoss Stalker being trash in PvZ (at any point in the game) and PvT after early game.
What spot does Stalker take in PvZ other than being AA and a wall blocker? NONE.
Sure, stalker are pretty good being a wall with their quite high health total in the early game, but are you really going to say that makes it okay? It takes 3 hit to kill a ling.
The other job it takes is to deal with overlords that come to your base, and you get blink to fight against mutalisk in Zest’s Glaivedept because you don’t have access to phoenix opening glaivedept.
Stalker really don’t have a place at all in PvZ. PvT early game, sure, they can be brutal, not gonna disagree with that.
They are an average allroundertool that doesn’t scale that good in big masses due to their blocky nature and rather low DPS.
Their mobility factor isn’t really a big thing in agression, due to quicker reactionary playability as zerg, but it’s still there defensivly and especially offcreep.
They are decent against roach/ravagers, good at denying scouting and vision, and once mutas hit the field or it gets into harder lategamestages with trying to have quick engagements against broodlords, they get way more present in the game.
It’s quite obvious that you use other better fitting tools rather than spamming them if you play against lingheavy plays, same like you do not spam roaches in marauderheavy games.
Actually you’d be surprised. 
Stalkers are really good against an early roach timing attack (cue extra damage against armoured). Coupled with immortals, and with good prism / blink micro, they can actually chew through a roach ravager army which may be bigger.
Let’s not forget you can also kill that early OL at your natural or deter scouting OLs from knowing your strategy (OLs are armoured too!). This is more crucial than most would think because many forget that Z is a reactive race, not one that can really plan a lot ahead like T or P. Imagine planning for a DT drop / oracle only to have a set of glaives adepts shade in. Any Z player’s face will turn sour.
For late game, they are good against broods too. A set of stalkers can blink underneath and easily snipe 2-3 really quickly. Or if there are ultras, stalkers give more micro-ability to prevent splash or kite with blink as opposed to just immos alone. A group of stalkers can always quickly dive into the main of a Z base and snipe key tech structures and still make it out. And of course, they can be warped in en-masse vs queuing up in the robo bay.
But if your key concern is lings only, I’d say that they were never intended to be a good counter to lings. Just like lings will rarely be great against zealots.
As mentioned in an earlier post, stalkers are not intended to be used in all situations or particular situations that you want them to be. At least not in the current meta.
