Here is my Boros deck that I drafted in BTT

Lands (15)
8 Plains
7 Mountains

Creatures (16)
Priest of Ioas
Favoured Hopilite
Akroan Crusader
2xTravelling Philosopher
2xCalvary Pegasus
Akroan Hopilite
Impetuous Sunchaser
Leonin Snarecaster
2xWingsteed Rider
Spearpoint Oread
Lagonna Band-Elder
2xElite Skirmisher

Spells (9)
Titan Strength
2xFall of Hammer (picks 1 and 2)
2xLightning Strike
Ordeal of Purphorous
Battlewise Valor
Revoke Existence
Dauntless Onslaught

So as you can see my curve tops out at 3. So do people think 15 land was the right call?

No. You need to hit 2 plains by turn 3. You can only do that with an almost-guarantee if you main deck 10 plains. You just made your best card worse.

EDIT: Sorry, I meant 2 plains by T3.

But to answer your question, yes, I have played decks with as little as 14 lands, specifically the mono-green archetype from M14 limited using lay of the land. Probably my favorite deck from the format.

Just looking at the Karsten math... you actually want 10 mountains and 13 plains to cast the 1 drops on 1 and wingsteed on 3... well that's not going to happen. But 8/8 seems about right. This deck might actually be WORSE with a phalanx leader.

Phalanx Leader would totally rock instead of the Oread. Or the Elder (no enchantments).

What the man said. You have no card draw and almost no scry, so you need to make sure you hit your land drops by playing lands. If you can't play your spells on curve, you will not win. You need to play a trick and a critter on turns four and five.

How did you do?

I really want 16 lands here, just for another plains. The spells are all really good... I would've cut the most useless expensive creature.

I went 2-1 (2-0, 0-2, 2-0). The games I won, I won in 6 turns or less. My last hand was just insane. Mountain, Plains, Plains, Crusader, Pegasus, Wingsteed Rider, Wingsteed Rider. Proceeded to draw Dauntless Onslaught and won turn 5.

The match I lost I actually flooded game 1. Kept a 4 land 3 spell hand and drew 4 land in a row (I don't know what the odds are with that but low). The second game I had my opponent on 1 life and he fought back due to Whelming Wave.

In retrospect, I would have cut the Priest for another plains but would have sided that out for game 2 if I won (i.e. if I knew or was fairly certain I was going to be on the draw). I often do this when I am playing a 16/17 land or 17/18 land.

You shouldn't keep a 4-lander when you're only playing fifteen lands, as you're basically conceding a turn where you're going draw land instead of action, and possibly two turns. It sucks you drew 4 lands in a row, but it happens. I've definitely lost to drawing 7 lands in a row now 3 times.