I have researched the life of Bill Diddel rather extensively and have written about him before on this website.
I would suspect the reason Diddel (not Diddle) has not received more acclaim is that he generally worked with modest budgets with little earth-moving capability and was, therefore, a strictrly lay-of-the-land golf architect. That also is a reason Pete Dye and others are devoting so much of their time to fingerpainting over some of Diddel's work. At Speedway (now Brickyard Crossing), Diddel designed the original course in 1929 with 9 holes inside the Speedway track. He re-designed it in the mid-1960s, with all the holes on an 82-acre rectangular tract outside the tract. In the early 1990's, Dye and Jason McCoy (his project manager, now head of Greg Norman's design team) rebuilt the course (with 4 holes inside the race track), and the last I heard the price tag was between 6 and 8 million dollars.
When Diddel got some decent land with which to work (much of Indiana's available land is pretty flat), the results have been excellent. I would think anyone who wants to sample Diddel at his best should try to arrange to play Meridian Hills C.C. in Indianapolis. Diddel favored north-south courses because one didn't have to be concerned with the sun and the prevailing wind in Indiana is west to east, and Meridian Hills followed that pattern. The greens, however, in my opinion are the best he designed, and one sees some Donald Ross(who designed Broadmoor about ten minutes away during the 1920s when Diddel was doing some of his best work) in the design.
Diddel also was a great golfer. Born in 1884, he won 5 Indiana state amateur titles in the first 12 years of its existence (1900-1912) and in 1950, at the age of 66, he qualified for match play at Highland C.C., which he constructed in 1920 to the routing plan of Willie Park, Jr., with 76-74-150 before losing in the third round. At age 82,he shot a 69 at Pinehurst No. 2 in competition, believed to be the most strokes below one's age ever.
I played several rounds with Diddel, and there were no gimmes. Wherever the ball lay near the hole, you (and Bill) had to place it a full putter length away from its resting place.
He scored better than his age more than 2,000 times and then quit counting.
Diddel's best courses were designed in the 1920's. When the depression hit in 1930's, he was able to build courses in smaller communities in Indiana as WPA projects and, thus, keep busy. Among those courses is Beechwood in LaPorte, already mentioned on this thread. Therefore, one frequently can wander into small Indiana cities and towns and find there courses of superior quality with sophisticated greens complexes. However, he still was designing courses well into his 80s.
Most of Indiana's subsequent golf architects learned from Diddel, including Gary Kern (whose remains active along with his son, Ron); PeteDye, who studied Diddel's work;Lee Schmidt, a native of Valparaiso, Ind., who worked with Diddel at Woodland as a youth, and who also worked with Dye and now is busy filling the west with courses, often with co-designer Brian Curley.
Diddel died in 1985 at the age of 101. He remains Indiana's most prolific designer and enduring golf icon. We were extremely fortunate to have had him for all that time.