Well, this is certainly an interesting discussion. I definitely believe that multiple definitions of "roguelike" can coexist peacefully.
My own personal definition is that the majority (preferably vast majority) of it's maps must be random. This stems from the idea that the core feature of roguelikes is to entertain the people who build them, which requires random maps. But that alone doesn't necessarily make something a roguelike. I think it's a combination of different factors that make something either more or less roguelike. The Berlin interpretation is great because it lists features which make something "more or less" roguelike without stating "this is a roguelike and all other things are not." There are features like ASCII, turn based, identification, and classes which make something "more roguelike," even though these features do not constitute a roguelike in and of themselves. And I think that's a good thing.
In terms of the Berlin interpretation being descriptive rather than proscriptive, that's generally also a good thing. The best definitions are descriptive rather than proscriptive. The modern study of linguistics insists on descriptive definitions rather than proscriptive definitions, as do many other formal sciences.
In terms of what clearly isn't a roguelike, maybe we've been a bit too quick to dismiss things as not roguelikes. This is probably due to a want to protect the genre, which is good. But, really, tile based games as a whole are not exactly a genre in and of themselves anymore. The roguelike community is probably among the last tile based RPG game communities there is, so perhaps we should accept tile based games as a whole, even if they lack many features of roguelikes. After all, where else are tile based games supposed to advertise and attract players these days? There is no temple of tile based RPGs, but there is a temple of the roguelike.
Having said that, it's still good to have some standard like the Berlin interpretation so that we can judge how many roguelike traits a game has aside from being a tile based RPG. And again, there's really no reason why multiple standards can't coexist. It would be easy to say things like "according to the Berlin interpretation, this is mostly a roguelike, while according to the X standard, this is entirely a roguelike."
Is glorg a roguelike? Well, it's a lot of fun, and it has random maps, which are a major feature of roguelikes. I'd rank it's "roguelikeness" as about 4 out of 10, with 10 being the max. 3 points for random maps, 1 point for fantasy-like dungeon exploration setting.