I agree with Padraig -- the vast majority of golfers (which reflects equipment makers and the clubs they provide for golfers) don't hit low irons very well (I don't carry an iron lower than a 5; I'm not that good, and thus representative of how most folks play the game). Every time I turn around, and listen to golf commentators/read golf instructional pieces, the advice is -- get rid of low irons, go to utility clubs. (I carry 5-9 irons, 3 wedges, driver-3-5 woods, 2 utilities ((effectively 7- and 9-wood loft)) and putter.)) I could probably get by with 11 or 12 clubs (dump one wedge, one utility, and maybe 3-wood), but not much less than that. There's a big difference in the length I get from my driver vs. 3-wood, and my 5-wood off of fairway lies vs. my more lofted utility clubs.
The only thing I'd disagree with, Padraig, is the notion that most golfers could get rid of even-numbered clubs. Most golfers can't play a hard-hooking 7 or a soft-fading 5; they generally know how far they can hit a 7 vs. a 5, and simply try to hit it as straight as they can. You'd leave a lot of golfers with in-between shots (in terms of distance), and force golfers to hit shots (a punch 7 for a normal 8-iron distance) most aren't capable of making. (Maybe that's worth pursuing, but I agree with Patrick -- you'd get lots of resistance in terms of folks wanting a the regular range of irons to play.)
Patrick -- my two utility woods replaced my 3 and 4 irons. I hit the utilities far better than my 3 and 4 irons, so I've kept using them. How is that any different than the goofy putter Furyk now uses that he took up a few years ago (or cavity-backed irons, or steel shafts, or non-leather grips, or...)?