I will quote GM John Cox from his book Starting out: 1d4!. "So hang on, you'll say, isn't this a Starting Out book? How can players rated 120-160 on the BCF scale (about 1560 to 1880 Elo) expect to grasp the intricacies of, say, the Botvinnik Semi-Slav? They don't need to be studying openings when the theory goes down to move twenty-odd when they don't know the first thing about the game.
Well, first of all, I think that's a patronizing tosh. Lower-rated players may not play as strongly as GMs, and they may not understand, recall, or have need of deep theory in their games to the same extent, but that does not mean they are not interested in knowing what the theory is, and it does not mean they can't improve by looking at it. Still less does it mean they shouldn't use the most thrilling openings in our game just because a lot of people have played them before (which is all 'theory' amounts to).
Secondly, I think everyone ought to play main line openings most of the time. If you want to be a strong player, then you have to play strong moves. It doesn't make sense to approach that by deliberately playing moves in the opening that aren't the strongest. For one thing, sooner or later, you will find that you need to play strong openings. And when the time comes, it is terribly difficult to make the change. These openings are not just the best, they are also the richest (in the end that's why they are the best) and hence the hardest to play well. If you don't make a start, it never gets any easier.
Look at the world champions: all of them (except perhaps Lasker and Petrosian) have played the main lines of their time. Mickey Adams has been quoted as saying that he feels the thing really holds him back is that he didn't play the main lines as White (particularly the Open Sicilian) early enough in his career. You may say there are counter-examples, such as Morozevich or Hodgson perhaps. However, I would say that these players have achieved what they have despite their devotion to the bizarre, not because of it. Morozevich is widely regarded as the strongest of all top players in the middle game: if he'd had equality out of the openings in San Luis and then played the way he did after that he probably be world champion now. And as a junior Hodgson had a fabulous talent (easily the equivalent of Short's): he may have reached number 100 or so in the world and he may have inspired the devotion of Tromp fans everywhere, but if he'd played 2 c4 his whole career I reckon he would have got higher. Nigel Short himself, who also had a notoriously ramshackle opening repitoire when young, was let down when he challenged Kasparov by his lack of mastery of the real main lines as much as anything.
. . .
If you're playing a main line and your opponent plays a move you have not seen before, that's fine. It'll happen half the time; there are many reasonable non-critical moves Black can play which aren't in this book; that's why it's 200 pages and not 10,000. You know you start from a good position: there are probably many more moves White can play which maintain a reasonable position and enable you to keep on with the plans you are used to. If the position is very tactical then if you know the normal move for your opponent and he plays something else one of two things have happened: either your opponent has produced a devastating novelty which has escaped the notice of Kasparov et al, or there is a good reply to his move and you have to find it. If you don't know the normal move then there still has to be a reasonable reply: dig in and find it. These are the moments that make good players, and you can't run away from them." - John Cox.
Although he was defending his choice for choosing only the absolute main lines in his book, we can take the basic ideas he touched upon and apply it to this situation. Your shortcuts might possibly be valid openings, but I doubt all of them are the strongest; otherwise people would play them more. Playing such openings may also eventually hurt your game. I know I am a little bit of a hypocrite for saying this since I play the Ponziani as white, but I am trying to switch to the Ruy Lopez with time.
Nowadays, there is a lot of opening theory. I prefer to use less known openings as a shortcut. Your opponent won't know about it, and probably won't find the right move! This also gives you more time to study endgames, tactics, etc. Do you take the shortcut or learn the theory?
Suggestions for sound shortcuts. On first move: b3, g3, Nc3, b4!?, f4!?
Other shortcuts: Bishop's Opening (1.e4 e5 2.Bc4), Vienna Game (1.e4 e5 2.Nc3 Nf6), and , the Scotch Four Knights (1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6 4.d4)