meaning - use of rather with noun and verb

Source

Rather a with a noun is more common in formal language than in informal language, particularly in writing:

1. It was rather a surprise to find them in the house before me.

Rather + verb
We can use rather to emphasise verbs. We use it most commonly with verbs such as enjoy, hope, like.

1. 
   

   I was rather hoping you'd forgotten about that.

   
   
   


2. 
   

   He rather liked the idea of a well paid job in the japan. http://dictionary.cambridge.org/grammar/british-grammar/rather

   
   

No 1. says that we use rather a+noun in formal writiing.what's the meaning of rather when we use it in this way? Are there other adverbs or words to replace the use of "rather" in 'formal' writing and in informal (spoken) language?

No 2. says we use rather with verb to emphasize verb. What does this mean? Does rather still carry the meaning of "more than average" or "to some extent" when we use rather with verbs ?