I would like to see a standard size (A px by B px) other than the suggested 16:9 ratio for timeline advertisements.
The reason I suggest it, is that many banner ad templates offer larger size banner which can be resized smaller if needed i.e.) 720x300 can be brought down to 400x250, etc. but that doesn't seem to fit in the timeline space; whereas other images at 400x300 (?) look fine.
Thanks,