Which is tough because ... frankly ... this adventure idea is coming out pretty darn awesome. At least I think so. Whether or not my players will think so is harder to say, but I'm hoping they'll enjoy it. It's got a wonderfully old-school sword and sorcery feel (Say it with me: "Howard, Leiber, Lovecraft, dread! Kill the monstahs, make 'em dead!") but has been nothing but easy to whip together. And with the more robust multiclassing and additional options provided by the online tools, putting together a setting that didn't suck has actually been fairly easy, as well.
I may have to take back some of the smack I've talked about 4E, especially now that it's matured a bit. Once you scrape all the WoW-iness off, there's actually a lot to like about it. And here I really must give big props to Goodman Games for opening my eyes, because they've really shown me the path for that "old school meets new hotness" middle ground.
I am a bit saddened to say that if this game is a hit with my players, that will probably be the death knell for S&S Saga, because as much as I like it, it will be superfluous. The real test will be to see if the game can keep feeling all old-school-sword-and-sorceryish once it gets into "the paragon tier" and upwards, at which point a lot of the published material will be trying to funnel the game into a lot of the sort of Planescape-ey silliness that just destroys fantasy games for me.  Supercalifragilistic S&S can be done — Fafhrd and the Mouser had some pretty OTT adventures for instance, and Kull the Conqueror had definite problems keeping his feet on solid ground — but it's hard to pull off without just becoming ridiculous.
But I think it may be possible if done deftly. The Icewind Dale computer games, for instance, provided a nice instance of something that was always D&D, still managed to stay fairly rooted in "reality" (for want of a better term) through the bulk of the storyline, and yet kept enough variety in the gameplay to stay interesting. And I'm certainly looking at both LotRO and Age of Conan to see how they do it. 
 Let me clarify that a bit — if the Planescape-ey stuff is in there from the get-go, I can accept it and go. It's not my favorite type of fantasy, but I can swallow it and play. It's when you try to start in a more "grounded" setting and then halfway through suddenly step through the Door To Anywhere that my mental gears grind and smoke. It'd be like having a TARDIS materialize in the middle of Starship Troopers — there's no law that says you can't, but it messes with my suspension of disbelief in a big way.
 I've always found it strangely amusing that Lord of the Rings, often cited as the classic example of "high fantasy," is actually one of the most "low magic" settings you'll ever find. I've seen a convincing case made that nobody in LotR — not even Gandalf — need be higher than 5th level in D&D terms. On the other hand, it's a matter of degree ... my lil' hobbitey warden in LotRO is 60th level and has taken on a balrog, an undead dragon, the Watcher In the Water, and more than one turtle the size of a good-sized house (Why are the LotRO devs so obsessed with turtles???) — but he still easily "feels" like he could fit into the LotR story. It's all about making the fantastic elements seem "natural" in context.