Question
My former contractor insists this is a viable design:

http://picasaweb.google.com/craigea/PublicAlbum?
feat=directlink

Is it? I've never seen a wall like this and I was expecting
a straight wall. Thank you.

Answer
If you are referring to the wall being level (up and down vertically) then no it should not be straight. It should have a batter (step back at each course of block) as it does in the pictures. That appears correct, although it looks quite sloppy(not even).
If you are referring to the wall curving along the adjacent concrete driveway the laying of the block is clearly very sloppy. The edges should properly align with the previous block and not change angels between each block as drastically as they appear to in these pictures.
Also I see drainage matting being used behind the wall in one photo on the left. This is not proper installation. These walls require compacted gravel behind them and a French drain at the bottom of the gravel. Also at a height over 3 feet the wall typically requires a layer of geo-textile reinforcement placed between the courses above 3'. This geo-textile is a roll of netting that is polymer reinforced and is buried several feet back behind the wall to keep it from shifting. The leading edge is trapped or pinched between the blocks and the trailing edge is buried and compacted back for several feet behind the wall. It requires digging out several feet of soil behind the wall. The only way they could avoid this is by having a consulting engineer perform soil tests showing it was not needed. Otherwise it is really rare that it would not be needed.

It is common for wall builders to cut corners and be lazy in my experience. It looks like your contractor is doing both.

Best of Luck

Sean J Murphy, Landscape Architect, LEED AP, ISA
www.seanjmurphy.com