Sorry to say so but in my opinion that's some really bad advice.
The problem is that too many people mix up Madden with the real NFL. In the NFL, sure, QB and LT are most important. In Madden, they are not.
In general, defense is MUCH more important in my opinion than offense when doing a fantasy draft. The logic is simple, on offense, the most important player is usually user controlled, so that limits the effect of player ratings, while on defense, you actually need all thos CPU controlled players to execute.
Sure, having Tom Brady is great, but actually, there's a dozen QB in the game that you can win any game with just as well, the only thing you can't compensate for is mobility, so I'd generally recommend going for RG3 or Luck simply because they are young, great passers and fast.
LT, like all other offensive line positions, simply isn't that important, you can pass and run the ball behind a mediocre line, it's not that hard. Drafting an LT that early simply means wasting a pick, you can easily pick up great young linemen in rounds 15+
In my experience, the most important positions in the game by far are LB and CB. Your CB needs to be fast enough to run with any receiver (so any CB with speed below 95 is, in my opinion, not good enough to be a consistent #1 CB) and needs good enough cover skills to stay with them through the cuts.
LBs are important on almost every defensive play, they stuff the run, they cover the intermediate routes, you absolutely do want fast, well tackling and hard hitting LBs with good play recognition are the difference between a poor defense and a shutdown defense in Madden, in my experience.
In general, the old saying is still true, Speed kills. You want fast players on every position you can get, especially on defense. In general, my early picks are usually spent on guys like Von Miller, Patrick Willis (if I can get my hands on him), Navorro Bowman, Jerod Mayo, Brian Cushing or Clay Matthews, Luke Kuechly and Mychal Kendricks are great rookies you can get for your backfield, too. One other player you absolutely want is Bruce Irvin, a rookie DE with 90 speed is not something you want to pass up on.
Drafting a CB early would be nice, but in my experience, there aren't too many worth taking early. Most are either too old or too slow, in general, I like going after Patrick Peterson as my #1 CB and you don't have to pick him that early.
Some of the players I like going after early on offense are Rob Gronkowski (guy catches everything), Calvin Johnson (dito) or Julio Jones as receivers, at RB, the only one I consider truly worthy of a high pick as Darren McFadden since he's the only guy combining strength and truly elite speed (David Wilson is a nice rookie with very good speed and strength as well). Speed is nice, but you can get guys with very high speed later on and the difference isn't that huge.
So that's my basic advice in a nutshell, always remember: This is Madden, not the real NFL. Just because something is right in the NFL, doesn't make it right in Madden.