I've been kind of sitting this thread out, but I think most of you know where I stand on this issue.
Cube has long been the home of "constructed quality cards, limited quality manabases". I play a ton of lands, and an ULD. Yet, drafting is still chock-full of choices. In the two forum-drafts we've done, fixing has been in extremely short supply for my seats, and I've had to limit myself to two-color decks. Both of which 3-0'd.
The traditional limited set has 14-card packs, so at the very least those can be lands. If you're running 45 lands in your 360, then 24 of those come from the "15th" slot, and you're looking at 21 more lands in a draft pod. I'm guessing most of you are running a healthy number of gold cards, so by design standards we're already running sets with some sort of multicolor emphasis. There's a reason multicolor emphasis sets print plentiful fixing at common.
45 lands among 8 players comes to 5.5 lands per drafter. Scale that to a 60-card deck and you're looking at the equivalent of like, 8 non-basics for a constructed deck. Fewer if any of those lands end up in sideboards.
I don't know how aggressively you're talking about trimming your land section, but you're going to notice the difference between 45 and 25 lands far more than the difference between 315 spells and 335 spells. Marginally increased design space, "in theory". In practice, less fixing means fewer colors played, and less room for sweet multicolor brews. If you're limiting your players to two-color decks based on a paucity of fixing, you're going to give your format a reduction in deck-diversity.
Regarding some "fetchland of choice" mechanic, I'd like to point out that 2-color decks can already play 70% of fetchlands, and 3-color decks can play 90%. I don't think such an implementation does a lot, other than allowing players to fetch basics more often if needed.