There is absolutely no way to make items good for competitive play. Their only purpose for for whacky chaotic games (thus party games).
Just thank Kneesus that you can turn them off.
(how would you even attempt to remove the chaos from items? Even non rng stuff like homerun bat and mr. saturns cause chaos.)
There is only one way where I think that items could be balanced.
https://www.youtube.com/watch?v=4As1E-EhRTs
Of course, limitations would have to be added, such as:
- Limited item pulls per stock, such as 1 item pull per stock.
- The option to choose which item you can carry before starting the battle.
- If the above can't be done, basically do what BBrawl did. A list of items that can be randomly pulled, but with different percentages for each of them. (Smokeball has a 50% chance to be pulled by BBrawl Jigglypuff while the rest have less)
- Figuring out how to give everyone the same "item pull" speed/a way to not mess up certain character's taunts. Or adding a completely new input just for item pulls.
- Balancing the items themselves to work with this feature.
- Determining what items would be "fair" for characters to pull. Stuff like Smash Balls/Pokeballs/Assist Trophies/etc are obviously out of the question.
- Bananas, since they are Diddy Kong's special move, should stay unique to him I feel. Meaning other characters can't pull them.
- etc
But once you do that and apply it to every character, items could theoretically be "balanced" for a competitive setting this way. The best way I could describe it is like having a one-time-use Smash Run Power (Smash 3DS) per stock, with some twists to it. The only problem with this is that it would probably take a lot of work to pull off, I bet.
As for the actual question of this topic, more characters and balance changes are always welcome. Although I always like being surprised by something new, as well.