Yeah, I agree. World cups generally gain some interest in a sport, but I think this one will fall a little flat, especially compared to 2015. A few reasons:
1. It's one of the least competitive international team sports I know. There are three serious teams that can make the final, and even those teams are barely competitive between them. It's like making a union world cup out of South Africa, Ireland and Samoa with loads of copies of Fiji as filler. There'll be three meaningful matches in the whole world cup, that might engage a large audience: Australia-England in the pools, the semi-final that contains two of Australia/New Zealand/England, and the final. This cannot hope to sustain the public interest when the tournament is done over a number of weeks. I wouldn't be surprised if even league fans tuned out of most of it.
2. It's a regional sport in the UK, which gathers the interest of only a select part of the North. The modern world strives on connectivity. Close community sports, like league is in the UK, I can't see growing very well. Union also has its hotspots in the UK, but they're much bigger and there are many more of them, making it easier to gather the public attention.