I dont believe it. I dont believe that you and massive percentage of player base was playing ladder because of ladder only rune words. If you would allow all uniques to drop and creation of all ladder rune words to nonladder, people will be playing ladder season anyway unless it is too short.
Main reason why majority of player base is playing the ladder is that feeling where you start from zero and slowly progressing again to be rich. Because when you have all things and characters, its get boring.
Also, your ladder items are transefered to nonladder, so the argument OP makes doesnt really make sense.