We had 5652 & 5654 last October with 3 kids and next month we have 5650 on the Fantasy, with just the two of us - all are 4e's (although we booked when they were cat 5's, so we paid the lower price).
Yes, the verandahs are twice the size of the regular verandahs (5650 is 4x the size!) but the cabins themselves are smaller than the other 4's.
The total square footage (cabin + verandah) is the same for all types of 4's (299 sq.ft. with the exception of 5650,& 5150 that have the added verandah space of the non-cabin beside them and possibly a few forward deck 5 extended verandah cabins as well) - the difference is 4a, b, c & d have a larger cabin and smaller verandah while 4e has a larger verandah and smaller cabin.
If there are only two of you or if you're willing to give up cabin space for verandah space, you're good.
With 5 of us between two cabins it wasn't bad, but with 4 in one cabin I'd stick with the regular 4e's.