Waddle Dee should be a playable character. If you think otherwise, that's okay, it just means that you're wrong.
Now, let's look at why Waddle Dee is so great.
1. He's soft and cuddly. Look at how much damage he does when thrown compared to Waddle Doo! Sorry, Gordo, I guess your spikes are nice too, I guess.
2. He's calm and collected. When he's thrown by Dedede and hits the ground or an enemy, he isn't angry, he's glad to be of service! After being thrown, he cooly waddles around, body slamming people every now and then to show how awesome he is. Look at Waddle Doo. After being thrown, he becomes angry and beams everyone! Not so calm and collected, compared to Waddle Dee.
3. He is strong for his size. Notice how in King Dedede's entrance, he is carried by four Waddle Dees. Those four Waddle Dees are holding up our heavy King Dedede, his kingly robe, his gigantic hammer (which he mechanized), and the throne that holds him! If it were Bowser holding this up, I wouldn't be surprised. But four Waddle Dees! If there were a Waddle Dee as huge as Bowser, he'd probably be wrecking havok everywhere. Except he wouldn't, because he's so calm and collected.
Considering how much damage he does when he's thrown, it means he isn't putting a lot of strength in when he hits the enemy. Shows how nice he is. Always thinking of other people, and not wanting to hurt them too much.
4. He's brave. When he's thrown by Dedede into the heat of battle, he STILL keeps cool and collected. He braves the coldness of the Ice Climbers stage completely naked! He bravely walks up to the enemy knowing that he will be hit in the face by accident! Jesus Christ, I'd be scared shitless and run off! It's amazing what Waddle Dee can do.
Now, you may be wondering how I think Waddle Dee's moveset should be like. Well, I have that all covered.
B: Blaster
Side B: Waddle illusion
Up B: Fire Dee
Down B: Reflector
Final Smash: Landmaster
It all works out!
Now you all know the greatness of Waddle Dee. He should be a playable character.