Please send tell me please. This makes very little sense. Is this Engrish brought to us by semi-fluent Asians? Nope. This is a phrase used quite often by normal players all over the English servers.
PST was an acronym for "please send tell." It was a quick way to be polite, which is ironic since politeness so often involves not rushing interactions. A combination of time and not paying attention to what words mean has caused it to shift to lose the specific meaning. Now it is a verb, rather than a full phrase for a request. It effectively has the meaning "send a tell to" and is part of the new phrase: pst me plz which can be interpreted as "send a tell to me, please."
In our new world we're seeing language change, as it always does. In many ways this is good. New situations call for new words, new phrases, and new meanings for old words. It would be cumbersome to say "We are looking for one more person for our group for heroic mode Utgarde Keep. This person should be able to survive and avoid damage better than average." Why say that when "lf1m, tank, H UK" says the same?
It doesn't say the same. Not just what we say, but how we say it, affects the perceptions of others. You might have heard "If you say plz because it's shorter than please, then I'll say no because it's shorter than yes." The idea here is "Slow down, use full words, I consider it rude that you cannot fully communicate with me. I'm going to be rude in return." This is entirely the fault of the reader, not the typist. There was no intention to be rude, that was entirely added by the expectations and standards of the reader.
Change itself is not bad. It is not the gutting of a language. It is the natural evolution. Change can be quite good, as in the case of the faster way to look for a tank. It can also be bad when change comes faster than people are learning it, especially when the new words don't add efficiency or meaning. "Pst me plz" adds no efficiency compared to simply "PST" and only adds one meaning: "I don't know/care what PST means."
Here's a list of words that are now used as substitutes for good: badass, sick, bad, sweet, the shit, awesome, fucking awesome, sweet-ass, great, leet, pwnage. I must admit to having used more than one item on that list. Why? None of these add meaning beyond "good" and if the context isn't just right, they can be very confusing as well.