I've literally been arguing and creating points every post that I've made. That honestly just tells me you haven't read my replies, which imo I'm disappointed because I took the time to view your arguments and points, and come up with a counter argument. This is a topic of discussion, don't start screeching just because someone isn't bending to your point until you convince them.
Lurkers are not overrated, because even a bad Lurker can get buckshotted, and still escape relatively easily, while landing potentially one slash that has a very high chance to outright break your bone. Here's a snippet of a Lurker who pounces me, struggles to click me for the majority of the stun, and finally lands 3 slashes before I get up.
I was at full health. The 1st slash went through, the second was absorbed, and the 3rd was softened -- and my head broke, along with direct brain and eye damage. The average Lurker can kill dozens of marines, simply by pouncing and clicking them two to three times, which almost gurantees them a bone break. Even if they're buckshotted, they can escape quite easily with their high speed. They are by far the strongest T2 caste.
Boilers are also great in almost every scenario -- they are even better in caves. Unlike Crushers, Boilers can gas diagonally through those twists and turns. The caves rather narrow pathways will force marines to either run backwards, or run forwards, they can't go around it. The only Boilers that actually die are the ones that set-up alone next to marines, which, of course they will be solo'd. Other than that? Let's say we're on an offensive siege, marines have been routed from Lambda podlocks and have retreated back to bar. A Boiler can set up pretty quickly and gas the bar FoB, forcing marines off of the cades -- leading to a xeno steamroll. It happens constantly. They are really really good, and in my opinion, deserve the SS tier.
Spitters and Sentinels are S tier because of their neuro. A sentinel can neuro somebody at the edge of their group and drag them away pretty quickly, and a Spitter can neuro two marines in a group, and simply slash one of them before fleeing -- their slashes aren't weak, either. Acid spit isn't used at all, because why would you use it when you have neuro? No castes, besides a Crusher charge, and Boiler's gas, has an ability that works great on groups of marines. Even an average Spitter/Sentinel can rack up kills by spamming neurotoxin on a downed person while dragging them away.
Crushers are still very situational in the cave. Not every part of the cave is a straight runway, with beacons lighting the way for the Crusher's path. LZ2 has narrow, straight hallways, which Crusher excels in, but is once again very situational.