/shrug.
most jokes have some truth to them. but i know what you mean.
and ya, I know Ferdi is a smash Masth... but im gonna argue with him anyways.
I find projectiles to actually be a hinderance when playing against him, as any DDD I know(even myself), would simply shoot out a waddle dee, and then simply duck behind it, forcing projectile characters to move close.
I must say, this statment really confuses me...
if you carefully measure the heght of DDD (even crouching), and compare it to his waddle Dee, you will find that DDD is bigger.
seriously, DDD cant duck behind a Dee, you can just jump and then fire your lazer/bomb/arrow/boomerang/pikmin/fire/light arrow/ect...
and even if DDD could cower behind a Dee, whats to stop you from being the patient one and nailing him when he jumps out?
belive me, DDD can use the Dees as a tempoary sheild, but it will never protect him from a camping mindset.
You also said that DDD's ground approach is one of his weakest aspect, and that's exactly it! By simply jumping(you also have 5 jumps whoamg) you become more versatile in order of approaches and tactics, as well as going over most projectiles anyway.
as mobile DDD is in the air, off the stage, his jumps are a verry slow method of approach, not even faster then running. so other charcters have the option of just running a way, jumping up as DDDs jumps lose power, and spamming away.
Aside from Toon Link(which I consider the best right now), no other character can really spam projectiles against him. Maybe GaW because his black sausage is so massive that it covers DDD's entire approach.
mario cant, Luigi cant...
but with a camping and jumping mindset, i think most others can.
I can speak from experience that olimar definitely CAN.
olimar can run away and latch pickmin onto the big guy, he can throw them faster then the Dees, negating their defensive properties, so your options are to run right at him and try to spotdodge/sheild as many of them as you can (leaving you open to a grab), or to take to the air, in which case he can run away, and jump to try to latch them onto you.
again, you can try to airdodge to negate the effect, but then olimar can just use this tether or other aerials to knock you out of the air once you come out of the dodge.
ive talked to all of the top DDD players about it, and their suggestion for an olimar who knows how to camp, is to pick up a secondary.
I picked Meta-knight... my MK sucks... bad, but i know he has a better chance against TBNJ in a competitive match.