"but I wonder what Licoln Walsh would have designed if he had access to todays technology or just lessons learned"
On paper at least, the evidence would seem to suggest that Dale Harder's technical vision is closest of the variations out there to that of Lincoln Walsh's, a single full range Walsh driver, along with the pros/cons that go along with that.
German Physics and OHM are both more focused on making the design more durable and reliable IMHO.
GP is more focused on using Walsh technology from the top frequencies on down and punting on the low end so that the driver is less inclined to destroy itself and hence more robust and marketable from a support perspective. Theirs is also more a "cost is no object" marketing approach.
OHM is also more focused on all but the top frequencies, also in the interest of making the design more robust and reliable at high output levels and hence more reliable as a solution for the masses. OHMs marketing scheme is more blue colar: find ways to make the technology more affordable for the masses.
Dale Harder has apparently improved on the robustness of the Walsh driver implementation from OHMs early attempts (the F and A) but my impression is that it is still more an issue with his design than the others.