"Amazing Seoul" symbolizes the city as the nation's traditional and cultural heart with plenty of entertainment facilities
I like your suggestion 100 times better, OP.
"Your Seoul and Mine"
"Hey Seoul Sister" ~ Train
Really like this.
The OPs suggestion was garbage, quite frankly. I should know. I'm the brain behind "Hey there Jeonju!" and "Ansan, you said what?" I submit "Your Seoul IS mine" as the obviously winning slogan.
Seould Out!
We Seouled our Seouls for Rock'n'Seoul!
I was thinking of something like "We built this city on rock 'n' Seoul!"