My yard is really small, so I'm limited to what I can do with the pond.
I expanded my pond two years ago, and at that time did away with any tall plants sitting in it, because, visually, they were clogging up the view and making the yard seem closed in. It was a good move.
I expanded again by 3' this past March, when I also added a bog filter. I LOVE the bog filter! Even though it requires a weekly flush, instead of being "maintenance free" as the pond shop people told me.
I thought I was happy with this set-up. But I ended up with an extra liner, and it's long enough that I could expand the bog filter one foot and the pond by two feet, which would give me (and the fish) an additional hundred gallons or thereabouts. So..., looks like I have another excavation project for this winter! - once it's cool enough that the fish can live in 5-gallon buckets while I dig, dig, dig! After Christmas would be good, so I can put on my Wish List a couple of things I will need from Home Depot and the water garden store.
In the interum, I'm toying with designs, like the idea of adding a waterfall in the middle, or a shallow end just for plants, or a divided pond with part being only for my fantails. Just milling it over right now.