MM pfren, You're right as allways because You understand the game well. You're the sober voice of truth on this site. Our problem is that we have not too many poetry and adventures IRL.
Aggressive openings

The openings are either sound, or unsound. It's the players which are aggressive, or defensive.
See what (say) Misha Tal, a tactical genius, was employing: His whole opening repertoire was purely sound openings, no dubious gambits at all in it. Tactical, sacrificial play came later on, when the conditions were ripe, and the position was not already destroyed by stupid gambit opening adventures.
I disagree with this black and white view... I think of openings which have negative reputations among the top brass, but no clear refutation, as "semi-sound", rather than all in or all out. Mind you that there are mainlines that could fall under that category, depending how much weight you lend engine evaluations.
...and Tal also famously said "There are two types of sacrifices: correct ones, and mine".

How does 1 e4 c5 compare with 1 e4 c6 ?
How does 1 d4 d5 2 c4 compare with 1 d4 d5 2 e3 ?
The first two are sound and good and each have their merits. The Sicilian tends to yield more active play earlier while the French is a little more solid/passive, but a couple lines in the French can be pretty wild too (check out the poison pawn winawer as an ex).
For the second two... the Queen's Gambit is (one of, if not) the very best opening(s) available to the White pieces, in terms of walking away from the board with a nonzero score. 2.e3 seems like the 9th or 10th best option for White right there. Why would you play that way? You're White. There's no need to make such concessions.

If You are interested in ultraaggressive play and ready to excuse unsound opening for tons of fun don't miss the best games of Emil Josef Diemer and his book 'fom ersten zug auf Matt' (from the first move to checkmate)
"... Very often, a certain type of commitment is bound up in a player's choice of opening. ... it is not unusual for a player to seize a long-term strategic advantage in return for piece activity or a lead in development. In this case the player with the better development has taken on an implicit commitment to undertake rapid action. Advantages such as a lead in development are inherently temporary, because when the opponent has brought out all his pieces the advantage disappears. A common mistake is to take on such a position, but not to appreciate that the long-term chances lie with the opponent. The result is a fatal lack of urgency. ..." - GM John Nunn (2006)
The most successful aggression is something the opponent is not prepared for, and the earlier you try it in the opening the more likely someone is prepared.
I agree about playing something that the opponent is not prepared for. When I play OTB and I notice that the opponent is making the moves fairly quickly, then I will go out of book. It might not be the most sound moves, but most opponent that memorized the line won't be able to play chess by fundamentals only.
Actually someone who is really booked up will counter your surprise with an equal or bigger one, like my 3. Qf3 against the Center Counter.
Well there ya go! Chess has been solved, and opening study has been reduced to 3 moves. Lets all go home now...