3 roll 1 suits can look great, but odd coats...from what I've seen they only look good in tweed/flannel. This looks like an orphaned suit jacket. Sorry my mod brother, but if you've got the matching pants, it'd look much better.
I have another similar khaki blazer and definitely neither are part of suit, (although I would love a khaki cotton poplin suit haven't found one that fits right yet).
Man of Kent said something similar about the two halves looking incongruent, I appreciate the constructive comments, and as I have so far garnered zero votes you two are probably not alone in your critique!
I used these light gray nailhead trousers to go for a spring-like look, but IMO the jacket looks better with navy trousers or dark jeans. I am coming to realise why a lot of people stay away from the light jacket/dark trousers combo as its not so easy to pull off as the reverse.