I think it looks too big in that it's big all over. I think the "big" blazer look can be attractive if it's "easy" in the right places and mostly a little long, and just a little big, but is not flattering if it's kind of boxy big and especially through the bust or armholes. Kind of a hard look to pull off since it isn't just a matter of sizing up, usually, but needs to be cut specially. Also like some styles an oversized look can work better on the tall, lanky models, whereas IRL a lot of gals look better in items that actually FIT.--sort of like a photo on the forum long ago where there was a weird loose fitting maxi or something on a model who as I recall I thought would look beautiful in a bedsheet, whereas I would not.
This is IMO, of course, and coming from having a high preference for figure-flattery over fashion-trending. If you're still trying to sort it out, try it on with some other items such as pencil skirt, over a sheath dress, or structured, slim things like that where slightly oversized blazers really shine.
I sympathize, though, because I've been worried about tossing tops or toppers that look too big and then finding that it's the "in" style. I've been trying to use some of the criteria above for me, so that I'm finding if the bust or the armhole area look too big I usually don't look good, and I need a middle ground, not too shrunken in the armpits to be comfortable, but not too big--hence I tossed several blazers out and am trying to be very particular about any new blazers.
