Should I switch my openings?

I am considering switching my openings. I usually play the Giuoco Pianissimo (don't laugh) but I am 904 USCF, and it will take too much time to learn how to play against all of those lines!

I am considering switching to d4 because it will be easier to learn.

I also play e5 as Black. I need to study the Sicilian more before playing it, but should I move on from e5?
 

If you want to play 1.d4 in order to avoid theory... Good luck. 

Maybe you could play 2.Bg5 against 1...f5 and 1...Nf6, but after 1...d5 sidelines are IMO less effective than the Queen's gambit (2.c4 (or 2.Nf3 and 3.c4)).

I would recommend reading GM Yasser Seirawan's, "Winning Chess Opening". Play what you are comfortable with and with what suits your style.

Opening Thoughts . . .

There's more theory than you think with d4, even if it has less first move responses.

Try to simplify positions into a guicco pianissimo structure you are comfortable with. That's the exact opening I used when I was your level (and still play from time to time).

Some openings can't be simplified into the structure you like. Check out my recommendations below.

At 904 USCF, openings should be your very last priority.

@pfren Doesn't mean he won't learn something from them.

Yes, this line of the Caro-Kann (used by Fischer to crush Petrosian) gives good attacking chances and is pretty sound.

There is necessarily something better to play for a beginner than the exchange variation against the French. I think the Ne2 Winawer (1.e4 e6 2.d4 d5 3.Nc3 Bb4 4.Ne2 followed by a3. This gambit (Black can play dxe4 and the Nc3 is pinned) gives white the bishop pair and a sound pawn structure. Black often refuses it.) is playable. Against the classical variation, then exchanging on d5 may be a good option (1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.exd5 exd5 followed by Bg5, Bd3 and Ne2). The Rubinstein usually doesn't lead to sharp lines, so I think a beginner can play it without knowing a lot of theory (or without knowing the theory at all).

I also used to play the giuco piannisimo! It seems to be the opening of those starting to play. 

Suggesting moves blindly is as huge mistake.  You are assuming Black will make the best moves.

If Black knows his stuff, the exchange is totally useless, even after 3.Nc3 Nf6.

However, pay attention to detail!

1.e4 e6 2.d4 d5 3.Nc3 Bb4 4.exd5 (I know you mention 4.Nge2 but making a point here) exd5, Black has not played 5.Nf6 yet so White might try the tricky 5.Qf3, but both 5...Qe7+ and 5...Nc6 are good for Black.  5...Nf6 is a huge mistake because of 6.Bg5! (A position Black must avoid!)

1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.exd5?! exd5 5.Bg5, Black must avoid 5...Bb4? Due to 6.Qf3! With advantage for White, but 5...Be7 gives white nada.  Full equality for Black.  Note in your post, you blindly give Bg5, Bd3, and Nge2.  If after 5.Bg5, Black does play 5...Bb4, and White blindly plays 6.Bd3, White just gave up a golden opportunity that he never deserved.

It should also me noted in the exchange McCutchen that after 1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.Bg5 Bb4 5.exd5 that Black is again in serious trouble after 5...exd5? 6.Qf3!, but it is rain on White's parade after 5...Qxd5!

Black should NEVER allow it, but that is one position worth knowing, that which results from 1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.exd5?! exd5 5.Bg5 Bb4?? 6.Qf3!

He/She will learn how to waste his/her time, and that is that.

At basic level... one should learn tactics, End and Mid game technique. Leave opening stuff till you get better.

When I started this account, I mainly focused on openings, but that was probably because I was already setting traps and stuff (not the best, though) in the middlegame and endgame.

In fact, all those "e pawn opening variations" are much easier to counter than after 1.d4. 

1. If the pawn move doesn't challenge the center, play d4.

the end. Reasonable opening play actually will help a lot, although I do recommend you switch from Giuoco Pianissimo. 2014 - 2017, I was a constant 800-900 USCF, played the Pianissimo because I didn't know other openings existed (lol). The reason I recommend you switch things up, is 

1. Online chess is great for experimenting

2. You can play a lot of games online, and get the experience you need with various openings

3. It makes chess more interesting! You can try a gambit, which is what I decided to do when I started this account.

Now, I still play e4 as white, occasionally f4 and d4. However, I play the Colle System for my d4, so it's not much of an accomplishment.

No. It's rather pathetic. 

Trying out new things can't be "pathetic". For many chess is a game, and not a sport. 

Even at beginner levels, some opening knowledge is important.

Oh boy, here we go again...

repeating myself:

At 904 USCF, openings should be your very last priority.

It's true that memorizing long lines does little help for beginning players. Learning openings is still quite useful, though. Mainstream openings demonstrate how basic opening principles (development, central control etc) intertwine with common themes (space, tactics, creating weaknesses etc) in a reproducible way. Certainly not a waste of time if done correctly. For example, many young players acquire the concept of initiative from aggressive openings.

@pfren You have the IM title and I fully respect that. But the recognition carries some responsibilities as well; hopefully you can give advice with a degree of consideration. Your words carry the weight of your title.

"

It's true that memorizing long lines does little help for beginning players. Learning openings is still quite useful, though. Mainstream openings demonstrate how basic opening principles (development, central control etc) intertwine with common themes (space, tactics, creating weaknesses etc) in a reproducible way. Certainly not a waste of time if done correctly. For example, many young players acquire the concept of initiative from aggressive openings."

Well said.