Was having a debate with a friend over which move is more important to Ryu. He claims the shoyuken is more important, I claim the hadouken. His fireball is his absolute primary zoning and footsie tool. It's the move that Ryu's use to dictate the horizontal space and control the opponents movements. So many times I throw fireballs to make them jump in, and then boom I hit em with a shoryuken which then gives me my mix up game. But it all started with the fireball. Other notable tools include the ex fireball in the corner which of course can lead to ultra. Also the fact the the fireball is an option select from low forward, which you can mix up with no fireball at all or a tatsu if they're FADCing through the fireball. So his hadouken has many space controlling uses and is the reason why I rate it so highly.
My friend however makes a decent argument too. He says a lp DP can lead to a full ultra, such an easy ultra set up. His DP is one of the best anti-airs in the game and of course leads to FADC ultra for good damage. If you have two bars of meter and ultra, it will change the way the opponent plays, which you can use to your advantage. This respect that he has for your two bars and ultra comes from the power that is your shoryuken. For me though I still think his hadouken is more paramount. Ryu is zoning and footsies first (in my opinion), and anti-airs and srk FADC ultra second. What are your thoughts?