http://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style#Brackets_and_parentheses

1) Some adjectives are (by their very meaning) gradable, and some not. For instance it would hardly make sense to assert that seven were "more prime" than five. Or again, she is a "more born" pianist than I am. Sometimes it is just a bit illogical: this carpet is less wall-to-wall than that one. Could one say: practice is more key to success than theory. Well, I guess I would understand.
2) if one googles or ngrams "is key to", it does come up. Sometimes arguably just a journalistic shorthand for "is the key to". For example: "information sharing is key to effective ..."
3) This all harks back to the big ask: what do you mean by "right" and "wrong"; is it common usage, or possible but uncommon usage? The exact criteria will affect all answers to the original post.
"Spurs boss Harry Redknapp opted to rest many of his key players,"

Does anyone else have the impression that the -er ending for comparatives is slowly dying?
I have just heard the weather forecaster reading from a script say "more wet"; and in speech people here seem to be saying "more easy" or "more easier", or "more happy" and similar examples.

putting 2.0459% into legal terms:
a) two and four hundred fifty-nine tenthousandths percent

b) one could recast the numbers and words using per mille
or parts-per-million; but the end result would be no clearer to my mind

c) 2.00459% two and four hundred fifty-nine hundredthousandths percent

d) caveat: I am no lawyer and no experience of drafting

http://lawprofessors.typepad.com/legalwriting/2006/04/incorrect_use_o.html

Two point zero four five nine percent

People here would say 'oh' instead of zero but in a legal document zero would seem more appropriate.
Again 0.45 might be 'zero point four five', although people might actually say 'nought'

@LLJ Well I really didn't understand your sentence on first reading so could I suggest:
"My greatest passion in life is creativity; put it together with art, food, or wine - well then you have my attention!"

yet ‎(not comparable)
1) (usually with negative) Thus far; up to the present; up to some specified time.
He has never yet been late for an appointment; I’m not yet wise enough to answer that; Have you finished yet?‎
2) Continuously up to the current time; still.
The workers went to the factory early and are striking yet.‎
Addison
facts they had heard while they were yet heathens
3) At some future time; eventually.
The riddle will be solved yet.‎
Shakespeare
He'll be hanged yet.

:from wiktionary.org
your example seems to be a less common usage these days

a) "you're" is short for "you are" - "I hope you are well " sounds ok so the answere is "you're".
"Your" sounds the same but indicates possession (compare we - our / you - your) ; "I hope your health is ok" is correct.

b) Who is seeking? Answer: "our client"; singular or plural? = singular; therefore "is" is correct. Thus either: "Our client is seeking" or "Our clients are seeking".

c) "Our client seeks" is fine, just perhaps a little more formal in this context.

Some people of a certain generation and background (like me) can recall being told at school NEVER to use this so-called "ugly" (ie lower-class) word.
Quite why the word "get" was deemed bad was never explained, and that indeed is the question.
'Get' has been in English an awful long time and is widely used:

etymonline.com/index.php?allowed_in_frame=0&search=get

Nonetheless, for examinations/academic writing I do still teach my students to consider using a more precise word such as "obtain/receive/become", if only to demonstrate a wider lexis.

However there are phrases where "get" is the only natural choice:
"They became married" would sound quite odd.

I would suggest there is little wrong with sentences like "The hard disk got erased by mistake" either, where get=become befits the situation.

As to why "people" use "get" so widely, well I think it might have something to do with it being somehow harder to formulate the sentence without "get" in some situations. But who are these people? Be not peeved, life is too short.