for a two season bag, I went for a good quality synthetic. I was filled with "qualofill" which is supposedly a cleverly designed proprietary material. The make was Snugpack which, from memory is/was Cotswold Camping's in-house brand - I guess it's mid range quality wise. It packs down to a maybe 12" x 5" so small arm enough for luggage and warm enough summer camping in UK or Europe. No good for Glencoe in winter, and I did get cold in the Alps (campsites not glaciers) n summer too, but still a great 2 season item. I have a blingtastic Mountain Equipment top-of-range down bag for the winter which was worth every considerable penny but needs more care and was a log of dosh
the synthetic bag can be stuffed in washing machine if it gets pongy, is warmish for it's size being a reasonably high quality one, and being lots cheaper than down you don't worry as much about it.
If I replaced it I might consider, like you, a two season down bag, but would probably end up with a good quality synthetic again. Top quality Down for winter though, despite cost