Without knowing the age and circumstances of the wall, I'm guessing that if the builder used unreinforced plywood and it bowed like this, it's going to have other fatal weaknesses, too. (It looks thin, too, so that's another indicator of short life span.)

I don't believe your plan is sound and that you'll end up with a somewhat less wavy veneered wall. Unfortunately, there is not space in front of this wall to build another one and cover this one up. I think the real solution is to demolish this section of wall and rebuild a better one. The picture doesn't indicate the total length of the problem. Hopefully, it's short and not an impossible project.

I'm mostly in agreement with yardvaark. Certainly the wall was built by someone not knowledgeable in how to form for a wall (maybe a homeowner?). The wall does point out the fact that even when done by an amateur, poured concrete walls are often long lasting.

If the wall is 2ft high and has no lean or evidence of failure, then I think it is likely that there is suitable footer and probably rebar tying the wall to footer. It's a shame the forming was not done well.

It looks problematic to do a veneer on this wall. The footer does not appear to extend far enough in front of the wall to provide support for the veneer. If not, only thin light weight materials can be used for the veneer. Getting the face evened out for a thin veneer is beyond the skill of most, even those who often work with concrete. The likely result would probably disappoint you.

I would suggest breaking out the wall to the footer. The footer may or may not be suitable for a new wall. Add to the old footer or pour a new one to be slightly higher than the walk. Form for a new wall with the wall face 4 inches back from the edge of the footer.The result should be a perfectly flat wall where even a homeowner could do a reasonable job of installing veneer.

If you decide to go this way I can give you directions on how to do a homeowner style of forming and how to do drainage through the wall.

Thank you Yardvaark and pls. I had an inkling that might be the case, but I guess I was being too optimistic. Pls, very good point on extending too far for the footer, I hadn't considered that.

Demo of the existing wall was a bit more work than I expecting to do myself. Any ideas on cost to demo and redo the retaining wall? It's about 25' long, 2' tall, 6" think. There are also utilities nearby, but I'm not sure where they come into the property (water shutoff valve is about 6' from the wall).

Thanks again!

"Getting the face evened out for a thin veneer is beyond the skill of most, even those who often work with concrete." I think this is an important point. I've done some occasional brick/stone-laying, attached veneer, etc. and I would be very afraid to tackle this project with the goal of smoothing things out. I know it wouldn't turn out well. It's hard enough when the substrate is straight! :-)

Taking the wall out would be a lot of hard work for a homeowner. A rented jack hammer and a heavy sledge would work but more effort than I would want to do unless it was necessary. But then maybe you have a couple of football playing sons for the task. There are two many variables to even guess what someone would charge ...like room to use heavy equipment and finding someone with a good match of equipment to do the job.

If I understand, the wall is in sound condition and the only problem is one of appearance. You may be suffering a bit of tunnel vision in only considering a masonry veneer.

One solution might be to cover the wall with plant material. trailing plants could be grown above the wall and allowed to hang over the wall. You could also drill the wall a little below the bottom and grow something like clematis or ivy through holes to cover the wall.

Another solution would be to mount horizontal 2x4s with standoff separators to keep the wood off the concrete. This would even the wall surface and provide the support for lattice, vertical boards, or some other decorative finish.