Actually it would be in Muju and I'm sure with such a big attraction they will accommodate for the night life. They are already set up as a tourist place for most part as Muju is a big ski area for Korea, Japan and China. So having the Taekwondowon there would give them tourism during the off-season for skiing. BTW...There is nightlife in Jeonju after 8pm...you just have to know where to go.
It is a big attraction in terms of size, but how many people will really visit it on a regular basis? The Kukkiwon is in Seoul, and for the most part there are very few tourists there at any one time. I always visit the Kukkiwon (there and kyobo) when in Korea, but Muju, I don't know if I would go everytime.