"If that weren't enough" is a phrase that's always used ironically. It means that there was already "enough," but nevertheless, something more was (or will be) added. The reason why the phrase is "that weren't" instead of "that wasn't" is because it's subjunctive. It's describing an imaginary or hypothetical state. Many native speakers don't understand this, so they'll instead say "if that wasn't enough." You'll also hear people say "as if that weren't enough," making it even more clear that they're talking ironically about something that is not really the case (it's plenty, but it's being treated "as if" it weren't enough).

It's an ironic way of saying, "But that didn't seem to be enough branding......"