I'm not so negative on the project as the others since while I do have a great credit rating I have relatively low spend -- paid off house and car, etc., at this stage of life there's nothing to "spend" on. With your spend and your decent credit rating, you should be able to get a free ticket somewhere every year, especially since it's just one of you. Well, not with Discover, but if you qualify for Discover, you certainly qualify for another credit card that offers better rewards, you just have to figure out what it is. I don't know what Citi's problem is. We haven't had any problem with them but we're long time homeowners. As others say, it is worth calling them and politely asking them to take a second look at you, especially if you hold no debt other than your mortgage.
You may not be starting at the top with business class international tickets twice a year but you can get a free ticket somewhere, and I doubt you expected to start at the top of your ultimate goal anyway. Hotel for the single person is easy -- there are couch surfs, airbnbs, friends and relatives who will put you up for an night or two, on and on, to help you avoid the chain hotel trap. Your first free trip or maybe even your first free trips may be domestic, but you should be able to take a free air trip every year and probably twice a year since there is only one of you. It might not be international right off the bat you are lucky to live in one of the largest, most diverse countries of the world, so rather than sitting at home, you should take at least one trip a year just to get your feet wet and get the instant gratification reward that keeps you working. It can't be all grim credit repair or people lose motivation.
Also some people generate "spend" by doing a lot of churning of moving cash around different payment processors, the Fidelity bank account, other bank accounts. I personally don't see the logic of it, since it seems TO ME as if the cost of defending an audit will wipe out the value of the extra miles, but there are a lot of people earning the miles that way so if that's what you're hinting at...yes...people are doing it. Whether it's worth it for some air tickets is a question only you can answer. Some of them know that SARS (suspicious activity reports) have been filed by banks, stores, etc. with the Dept. of Justice on their activity, and apparently they just shrug it off. I sure don't advise it but you will certainly see the activity hinted at on this site. If you're asking for more details, I would say take a closer look at Miles Buzz and then find the bloggers and follow those who give the most detailed guidelines. For myself, I prefer to stand apart from that particular activity. But, admittedly, some of these guys have millions of miles...so it's up to you whether it's worth it.