The first couple of seasons can be a bit of a slog at times, granted. However, make the effort, it pays off later on, IMO. DSN gets really consistently good in it's third season. This is when thewy stopped trying to be "TNG Jr." and decided to just be the best DSN they could be.
And as far as Avery Brooks' acting goes - I've never understood the criticisms, honestly. I think he's just fine.