You're absolutely right. I think I got the impression (perhaps incorrectly) that he would not be using hops at all, even for bittering. Herbs etc. can certainly provide great flavour and aroma, Fraoch is a wonderful example. I would imagine it must be difficult to get some consistency as one "batch" of herbs/spices may be more potent than another. I suppose experience would help to adjust the quantities though. I think I read in 'Radical Brewing' that Fraoch also contains Bog Myrtle? My mind could be playing tricks on me though.