NW and DL are still different entities operating different routes and different inventory systems. Pricing is not going to be completely aligned until those differences are resolved.

For right now, the only thing that's really changed is that NW and DL are no longer "competing" with each other. You should still be checking both airlines as if they were separate, because in essence, they still are.

As for nwa.com being "junk" since DL came on board, that's quite a broad stroke, but I can assure you that it's no more "junk" than it was before the merger.