The whole code is ancient. And I have a great dislike for software that does not use autoconf. The killer reason that I don't use nn anymore is that I moved to a new news server a while ago, and nn was incompatible with it. Besides, nn is too bloated. Bloated software is a bad thing.
Programs get bloated over time.
Software tends to carry tons of dead code with it. SLRN is small and fast. SLRN can use colors. SLRN is configurable. SLRN just works with all NNTP servers I tried it on.