So you're basing a match up solely off an infinite? What are they going to do without their infinite? There are a number of neutral stages that have platforms that D3 is unable to really do his infinite. The only neutral you truly have to avoid is Final Destination. Even so, you could simply go ZSS if you felt that D3 was abusing his CG's. An infinite alone does not determine a match up.
Samus may lack the KO potential to defeat D3 at an early percent. But I assure you that Samus can gimp her opponents, spike her opponents and even have them pushed further out with her zair. Your barrage of projectile may not surpass D3's, but your zair goes through everything and goes long range. If you're getting grabbed, chances are you're not spacing good enough. If you're on a stage with platforms, use those to your advantage. As long as you're out of his reach, there's not much he can do to you.
If you can get him off the stage, learn to edge guard him. Use whatever means to keep him at bay. Don't just think, "Oh, it's D3, no point in really trying." Seriously figure out what you can do to D3. I don't believe it to be 100-0, D3 or even 70:30/65:35. If anything it's probably 60:40. At least if you learn the match up, you won't have such a hard time with him.
Learn the match-up? Samus mains worry more about D3 knowing the match-up than anything. It's not the infinite that defines the match-up either, it's the simple fact that D3 is a good character. He has a simple way to rack up damage and easy to use kill moves that need no set-up. So what if Samus is a heavy-weight? Racking her up shouldn't be a probably because d-throw never increases in knockback.
She can't spike a good D3. U-air comes out faster and outprioritizes it. For that same reason, it would be horribly to be above D3, including platforms. U-tilt goes through all neutral platform stages except for Smashville.
Z-air may go through everything but shield blocks everything save for a grab. And risking your own grab will reward you half the time, the other half punishing you even harder.
Now I'm not saying this match-up is unwinnable. Samus can easily rack up damage once she gets started. Her z-air does beat D3's waddle dee spam. And her missiles can do some major shield weakening into eventual z-air shield poking. Not to mention knocking him off the stage followed up by some good edge-guarding results in a free hit once D3 up+bs. In fact, practically the only way to land the killing move would be to force D3 into his up+b. In fact, that's practically the only way to legitimately play the match-up: racking up damage long-range and forcing his Up+B.
But once you're pushed off the stage, don't expect the D3 to sit there and wait; D3 has a fairly decent edge game as well.
We don't argue that the MK match-up is 100-0 MK's favor. Rather, 80-20 (or in some extreme cases, 90-10.) D3 can't be above that and I don't think he's as hard to face as MK. So take whatever number you will.
"Knowing the match-up" is great and all, but if the D3 knows the match-up too, you're back to square one and the obvious truth: D3 is a good character and Samus is an average one.
We might as well keep this thread open so we don't have to discuss the D3 match-up in the other thread (if we even get there.) Not to mention it is the iconic bad match-up for Samus so it should hold it's own thread anyway. =/