Question

Which term would replace the underlined word to give the sentence a more positive connotation while not changing the overall meaning?

Answer 1

Laid back term will replace the word.

The term  laid back, which implies loose, is a casual and metaphorical term that can best substitute the word sluggish, however without the negative implications. It ought to be noticed that the word is casual, so that in specific settings, most eminently formal settings — like correspondence with a specialist figure or in scholastic settings—, it would not really be the best word decision.