At what level does being very aggressive stop being useful? Aggression is very good against weaker players. But too much aggression is bad, and the higher the level of play the more you need to dial it back to be safe.
What is the point in ratings in which one should look more to playing positionally and stop going all out for attack and tactics? This is in order to avoid losing with barely inferior moves that a weaker player could not find a good response to, but a high rated player can refute.
Whether aggresive or not, good chess works against all players. Bad chess does not &quot;work&quot; against anyone, but you can still beat a weak opponent in spite of it.
There are positions that require aggression, others that don't. After 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4. Nxd4 Nf6 5.Nc3 g6 6.Be3 Bg7 7.f3, aggressive play is the only way you can beat a GM. After 1.e4 e6 2.d4 d5 3.exd5, you should expect to be in a quieter game.
There's also a trend towards aggressive play requiring more opening theory to rely on (as mistakes will pay a higher price)