No credit card required
Browse credit cards from a variety of issuers to see if there's a better card for you.
I think the TR has faded around here mostly. Comenity in general along with the others you listed should be avoided unless you have a true use and need for a particular card with them since you're rolling the dice in so many ways by accepting one.
I recall seeing some shutdown threads on it but, recent activity doesn't seem to be too much unlike what it used to be.
As to the whole 10K/70K thing..... If you were to carry a balance like that it wouldn't hurt that much on scoring since it would show your lenders you ability to handle larger non-installment balances. You might even go to pull the handle on CLI's and hit a jackpot!