At this point, you wouldn't use what I feel is one of the best benefits of concierge - the booking of a cabana and other hard-to-get excursions. So depending on the price you would pay to upgrade, all it would get you is access to the concierge lounge with treats and happy hours each day. Wonderful coffee drinks from the coffee machine in there, btw, so if you like lattes and other fancy drinks, I suppose you would save money on the drinks you would normally order at Cove Café, plus cocktails before dinner. You receive access to the sundeck, and a special meet and greet with a character. I think the furnishings might be a little nicer with some higher end wood finishes in the room, but the same amount of living space. The concierge hosts are very helpful if you need special assistance, and can book your spa treatments, character meets, tastings, etc. - saving you time from standing in line at guest services. They can also take care of changing tip amounts for you, but you will probably feel expected to tip them at least something at the end of the cruise, so there's that added expense. If I were in your situation, I would probably find it hard to justify at full price at this stage of your cruise planning.
However, if you can arrive early enough at the port and those rooms are still available, you may be able to get it at a fraction of the price of upgrading right now. If you go into it with no expectations, you might be pleasantly surprised if an upgrade is available.
We have always sailed concierge in a 1-bedroom suite - on both the classics and dream class ships. We love the extra space, and feel between that and the early booking benefits (not to mention that we love to spoil ourselves on our vacation), it will always be worth it to us. We have also had great concierge experiences, so I am sorry that you didn't have the same results. We would rather sail concierge on the Dream / Fantasy just because we love the lounge, and use it a lot for treats throughout the day and cocktail hour. We make close acquaintance relationships with our concierge hosts, and enjoy the feeling of belonging and friendship we get on board from them.
I know you'll have a fantastic time on your cruise regardless of which you choose. Have a wonderful time - we are also a little more than two months out on our Fantasy cruise, and it has been a long time coming, so we are very excited. Any
Disney Cruise is better than no Disney Cruise - ENJOY!!