Taking a dim view of something means having a negative or unfavorable opinion about it. To express the opposite sentiment, one might use antonyms such as "approving," "praising," "admiring," "lauding," or "commending." If one is optimistic about a situation, they may also use words like "hopeful," "optimistic," or "confident" instead of taking a dim view of it. Alternatively, one may simply use positive adjectives such as "promising," "encouraging," or "exciting" to describe something in a more positive light. Whatever the antonym used, it will convey a completely different attitude towards the subject at hand.