This strikes me as an overreaction. Plenty of attacking types get by just fine with immunities hampering them. Jolteon has done just fine for itself as an attacker despite (gen 4 examples alert) Pokemon like Flygon, Swampert, Hippowdon, etc. all being able to come in and absorb its STAB move. Yeah, it makes Jolteon less effective, but it's probably healthy that Jolteon has some decent checks outside of Blissey. I think the centralizing power of Dragons in the past has proven that. Since you basically had to run multiple Steel-types to compete with the likes of Latias and Salamence, the metagame got heavily centralized because, well, Pokemon as we knew it simply could not reliably keep up with those Pokemon in large part because of their offensive typing. Is it really such a bad thing if you can't spam Draco Meteor all over the place? Doesn't it force people to predict more, and isn't that a good thing? I don't think "we can't spam our Dragon moves early game" can lead you to a leap where they become useless or their effectiveness is severely compromised.
I think what's more likely is that Dragon-types become more like offensive Fighting-types, where the STAB has one annoying immunity (Ghost) and a few useful type resistances (Psychic and Flying especially) that keep it in line. I think it makes more sense than the Normal comparison largely because there just aren't that many Normal-types to abuse its neutral coverage. Dragon-types have way better stats and movepools across the board, have key resistances (and often immunities) that Normal-types don't, and are just better in a vacuum. And Normal's closest thing to Draco or Outrage is, what, Double-Edge? There are a lot of confounding factors beyond the typing itself that make Normal-types less than awesome. If you took Tauros, for example, and gave it Salamence's base stats, two 120+ BP STAB moves (one physical, one special) and Dragon Dance, it probably wouldn't be such a joke anymore.
...And this all assume that the Fairy-types will be good enough themselves to warrant usage and reliable enough checks to Dragons to make them worthwhile. I'd say it's likely but we don't know. (Not like it's bad to assume that, otherwise this is sort of a pointless thread lol and theorymon isn't a crime all the time -_- but yeah)