Well, I can't say I'm convinced the older model of flight sims (where you release the main game, then every 9-12 months release an expansion that contains multiple planes, a map, other things) is no longer viable as no one tries it anymore but Thirdwire. They've picked up DLC as well for individual planes, but in those cases they're mods of existing planes that require far less effort than an ROF plane (such as an F-4EJ out of an F-4E). The difference between an expansion and DLC is that an expansion bundles things you know everyone will want with some things people aren't sure about and might not buy separately. So you put a couple "must have" planes in with a couple "like to have" and a couple "never heard of them" and people buy them all on the strength of the big ones.
F2P is essentially an uber-demo, letting you almost play the whole game. Arma2 went the same route, and now the DayZ mod has spurred tons of sales for them. Not to say I think we need ROFZ or anything, just that I think F2P with limited planes was the easiest thing for them to do as far as making a demo so it made sense.
Anyway, I waited with ROF until ICE before I got it because I thought the original release was too light on planes and I didn't want to have to buy each one individually at the start. ICE was a great deal, giving you all those planes for a discounted price over individual. Keep in mind the current system of getting discounts when you buy several at once wasn't in place then. Now that it is, you can almost make your own expansion.
Maybe that would be the best solution for those of us wanting early years fleshed out? Maybe a "1915-1916" bundle? If there's doubt any individual plane would sell well, you package several early ones together at basically the same price people would be charged with the multi-plane discount if they bought all of them.
Think of it this way: it's like buying a movie with the sequel bundled with it for less than buying the 2 films separately. Ghostbusters 1 and 2 for example, where people might not bother to buy the sequel separately as they don't like it as much, but for $5 more than the original alone they'll go for it.
The Jedi Master
The anteater is wearing the bagel because he's a reindeer princess. -- my 4 yr old daughter