London system is actually very bad for beginner chess development. It's easy but quite dry and unambitious. It can teach bad habits as you are only learning to play on autopilot and not challenge the opponent in the opening.
Ruy Lopez, Queen's Gambit, Italian (particularly some gambit lines) or Scotch are all way better and more fun.
I agree with the fact that it’s dry, but it helps teach good principles, and can be a good base off of which you can learn other openings (for instance, the Trompowsky). I think the Italian Game is pretty good for beginners, and the Queen’s Gambit is also great. I do think the best beginner repertoire would be the Caro Kann, Italian, Pirc, Queen’s Gambit, London, and King’s Indian Attack. The Owen’s Defense, Trompowsky, and a Scandinavian are better for more advanced beginners.
The issue with that repertoire is that aside from the Queen's Gambit, all of those are very complex positional, waiting, defensive openings, and beginners usually are much more suited for attacking, not defending. I'd argue that that's actually a fantastic repertoire for 1100-1400 players, (advanced beginners) and Owens/Trompowsky/Scandi is a better repertoire below 1100 (beginners).
You do make a very excellent point - I teach chess classes, and for the most part, my students love the Owens/Trompowsky/Scandi as their main repertoire, with some other stuff on the side, like the London, KIA, and Queen’s Gambit.
What rating do you teach for?
A pretty wide range. My best students are 13-1400, and my less highly rated ones are 300-900.
Blitz or Rapid? Ahhh, unfortunate. I'm 1600, so I'm pretty far out of that range.
I have one 1600 student.
@SamuelAjedrez95, note that I'm not trying to give the best variations all the time, I'm trying to give the lines which will teach long-term ideas. Kramnik transfers to Tarrasch, Winawer transfers to Najdorf, Canal transfers to Ruy Lopez, et cetera. This is a "teaching" repertoire more so than a "winning" repertoire, though I tried to pick White's best lines in each of these as well because winning is fun.
It will teach you better to immediately start playing and learning the opening that you want to play in the longrun as you will become accustomed to the ideas of that opening. Choosing one line earlier and another later is just giving yourself more to learn.
The ideas in the Canal Attack are going to be very different from both the Ruy Lopez and the Open Sicilian. In the Canal Attack you will often be playing without the light square bishop whereas in the Ruy Lopez, you preserve it. Also the black pawn will often be on e6 rather than e5. The Canal Attack is a decent opening but it will not teach you the ideas of these other openings.
Canal Attack
Ruy Lopez, Chigorin Defence