I'm not happy about it, but the product is evolving, and frankly this is a (slightly) more tolerable change than some that have been mooted, such as the famous "16 segment maximum" typo on the AA website. As it is, we have more and better carriers, and many more destinations on the list than we had a year ago.
IIRC the 20-segment limitation is not that old itself, and the unlimited mileage of the OWE still makes it infinitely preferable to the *A or other mileage-based products.
I do wonder, though, how rule and fare revisions work with OW. The Vancouver operation is pretty opaque - does some airline nominate a new rule and the others validate it? Do OW core staff drop a bill in the hopper followed by debate? It'd be interesting to know how they evaluate or road test new rules or fare restrictions. (Although it's probably like making sausage - you don't want to know.)