As to the first complaint of using "they" as a singular third person pronoun - get over it. That is simply how people speak in American English. As Paul rightly pointed out, "they" is the only simple way around the "he/she" conundrum.

* It's usually not wrong to end sentences with a preposition...

That may be true, but the whole "don't end with preposition" rule isn't actually ENGLISH. It's Latin (English is a Germanic language, despite our Latin-derived vocabulary). Please read up on some Steven Pinker and John McWhorter if you have any other questions on these ridiculous, antiquated rules that don't actually apply to our language.

By the way, how can one use too many pronouns?

You should never capitalize / bold words (especially at the beginning & end); use context clues to give weight to what's critical.

You just made that rule up. That is simply our way of formatting - it is related to QuikScan abilities - highlighting crucial information so that someone can skim and article and take away the same message that THEY would have had THEY read the entire thing in detail.

As to how those of us with lousy "grammar" (grammar is in quotes there because I think most grammar rules are bunk, having nothing to do with the way we speak), who can't string together a sentence more than six words long, manage to land jobs at copywriters, well my friend, here's an inudstry secret: copywriting involves creating sentences that are only six words long.