The last point about chasing flushes and straights is very true. While mathematically you may be getting the right odds
to call them, if there are medium-sized raises, then you may well lose too many chips - if you lose 2/3 of your chips chasing draws, then when you do hit you'll only have about what you started with. To chase draws in a tournament setting, the stakes have to be low enough that the cost of chasing is cheap enough relative to both the pot and your stack. The draws work better as part of a more complete hand.
Also, in a tournament draws can be hands to raise with, because ideally everyone will fold to you and you'll take the pot on a semi-bluff, or you'll hit your hand. Sometimes a small raise will scare off a raise by another player, and allow you to get a cheaper turn card than you would otherwise, too.
Finally, pushing all-in before the flop is a relatively blunt instrument. Probably a better tactic is to make a fair-sized raise before the flop, and then raise the flop. If you can get it heads up for the flop, then the chances are the flop will miss your opponent. If you think it has (regardless of whether you hit your hand), then you want to raise the flop, with a decent-sized bet. 3 low cards is often a good flop for raising without a hand, as can a paired board. The advantage of this play is that you build a decent-sized pot and often get to steal it uncontested. You do need to make sure that you don't put too many of your chips or your opponents on the line - ideally you want to be against someone with less chips than you, with, say 1/4-1/3 of their chips in the pot, because you can then raise enough to scare them off a missed flop, but win a decent pot. It doesn't always work, and can backfire sometimes, but you have to compare the risk factor of this kind of play against pushing all-in pre-flop.