I'd like to deepen the pond this year and make it slightly bigger in
diameter. The plan was to move the shrub (flowering crab) and replace the
waterfall with a waterwheel. I was just looking at those stone blocks that
they use to raise flowerbeds and thinking I could use these to deepen the
pond.

But I can see several problems:

One, it may look like crap, giving the pond a wishing well look. I don't
have a lot of room between the walkway and the pond's edge.

Two, I don't know enough about these stones (I've seen a couple of styles)
to know if they would support the liner. Although I currently have two
layers of pavers below the water line on the top 'shelf' of the pond to hold
the liner in place before it gets folded under. Something similar might work
again. Any suggestions appreciated here.

Three, would the gaps in the stones let critters chew holes in the liner or
expose it to the elements. I guess I'd need to backfill the bottom rows (two
or three) and then put the cap stone on top of the liner.

Four, Might provide easier access for critters, raccoons etc.

Five, this would make it difficult to add a water feature (wheel or
waterfall) with the raised edge. Creative ideas appreciated.