Disclaimer -- expressing a personal opinion here, not postulating any fact or rule....
While i agree, historics like "Wabash" have a elegance and simplicity thats appealing, I happen to believe that those two traits can be expressed in modern iris. In fact, I selected and registered these two with those two principles in mind. I agree that the authentic form of a tall bearded iris bloom can be obscured to some extent by an excess of ruffles, wild conflicting color patterns, etc.
When these two seedlings bloomed for me, I selected them over their more ruffled, undulating, bubble waved siblings. I happen to appreciate a simpler, more tailored form as opposed to a wildly ruffled composition. I still prefer rounded, broad, and wide standards and falls, over narrow and strap shaped, such are Wabash and others introduced in the '30's - 'early '70's and a bit beyond, but that is my preference and not an absolute rule that other hybridizers need to follow.
Marching to Zion - (Metler '11)

Endless Ocean - (Metler '11)