Really: "Avoiding this word is a really great idea."
Reason: A really great idea is the same as a great idea. If you need to emphasize something, such as the "greatness" of an idea, use a single word that means what you are trying to say, e.g., "Avoiding this word is an excellent idea."

Think: "I think the government should stop people from writing poorly."
Reason: If you write an opinion, the reader understands that you also think it. Just say what it is you think, e.g., "The government should stop people from writing poorly."

Sort of/Kind of: "Using these words is sort of annoying to the reader."
Reason: If using these words is only sort of annoying, you haven't told the reader exactly what it is. If it is annoying, say so: "Writing this way annoys the reader." If it is not annoying, tell the reader exactly what it is, e.g., "Using these words bothers readers." Use words that mean what you are trying to say, and give the reader exact descriptions. This also applies to "kind of."