I love RSS, hope it makes a resurgence. But I don't think the only reason for the death of RSS was the discontinuation of Google Reader. RSS can become very messy super quickly, and I think we need clients that don't look like the ones we know from 15 years ago, but ones that help users to keep their subscriptions neat and clean.
I know this is subjective, but it's so hard to find a good rss reader with a modern UI and isn't inexpensive/free
There's a Reeder 5 and the two improvements (for me) that it has over 3 is that Twitter probably won't say "outdated browser" and refuse to show tweets and support for adding newsfeeds directly. I think MacOS added support for this after Reeder 3 was released.
Mixing the two readers is fine because Feedly is keeping track for them. If Feedly were to start charging, I'd probably start using NNW exclusively since they provide the option of using iCloud to sync.