Modern OHM Walsh design speakers are without match I find in terms of their ability to go loud and clear (with the necessary amp behind them) for teh particular size and at the particular price point of each.
I think a lot of that has to do with the Walsh driver principle as JS has implemented enabling more output from any particular driver than might be possible using typical pistonic motion only driver design. If one reads up on Walsh driver operation principles, I suspect that is a result of the fact that sound leaves the cone at different frequencies from different locations along the cone. Also because the Walsh driver does not cover the higher frequencies, above 8Khz.
Lincoln Walsh's original design attempted to be full range. It succeeded fairly well at that but all implementations at the time were quite delicate and fragile and easily destroyed at high volumes if things went wrong.
Modern similar designs, like Dale HArder's, might have solved some of those problems, or I am confident at least are able to address them better to some extent, using modern technology advances at his disposal today that did not exist in LW's day.
Remember though that the largest modern OHM Walsh driver, like the ones in my F5s3s, appear to be only about 10" or so. I have not encountered it yet practically in my case, but that will become a limitation at some time, even if the design manages to squeeze the most possible out of a driver that size.
10" and even 12" bass drivers (not even wider range like modern OHM Walsh CLS) used to be common years ago, but few modern speakers use driver's larger than 10". Many modern speakers, including OHM to some degree, tend to use smaller drivers and be less efficient in order to fit better into most people's homes. Smaller lower efficiency speakers put more burden on the amp, especially to deliver high SPL full range sound in larger rooms. Huge, heavy, and expensive monster power amps, available to few, used to be needed. No longer the case however with modern Class D amp technology, which I consider to be one the greatest recent innovations in home audio technology. A perfect match made in heaven for JSs modern innovations with the Walsh driver principle.
The sky is the limit now for home audio enthusiasts with Class D amps. Especially when you toss a few into a sub cabinet along with a good quality 12" or 15" bass driver.