Leona is the simplest to dominate a lane with so long as you are willing to fight. If you get ahead with her, she'll do very well in teamfights by just engaging whenever someone gets a bit out of position. If you get behind, you'll have to play it very smart, and either peel well or support other champions when they make plays. At the very least, the ultimate can always be useful.
Braum is a bit harder to win lane with than Leona, but he's still perfectly capable of winning a lane. He is more defensively focused, taking damage for his teammates. His engage suffers, but his peel is stronger and his shield can provide invaluable utility.
Blitzcrank is a mixed bag. You can win a lane against a lot of people just because they get scared of Blitzcrank and play dumb. Grabs can also let you burst someone down quickly. However, Blitzcrank has shitty sustained fighting, he's worthless if you miss hooks, he's worthless if you get behind in lane, and he's very easy to bully and punish. Out of lane, all your value is in making good pulls. You have nothing else particularly strong going for you. In order to be good at Blitz, you'll have to be great at pulling and good at map rotation. He's easy to be bad at.
Janna is very different. You won't be winning lanes with her unless you are good with her or your ADC knows how to play with her (and many don't). You can win lanes, but it's not braindead. Later on, you are the strongest peeler in the game. That is a lot of teamfight value. Just don't ult enemies to safety by accident.