Having all types would do far more harm to the game than good. Some types would show up as weaknesses/resistances much less frequently (we already see this with a couple like Dragon and Colorless), and it gives little to no opportunity for weakness diversity in types. (Think about it. If Rock/Ground got split off as a type from Fighting, all Fighting Pokemon, minus Hawlucha, would be weak to Psychic.) There's also the fact that some types are already much smaller than others, and have little going for them as a result. Fire and Lightning in particular suffer from this, especially as there are so few Pokemon of those types. The smaller types almost invariably get far, far fewer cards. (Which makes sense. Given how few Pokemon there are of those types, repeats happen a LOT. Look at how many Manectric and Talonflame cards exist.)
The type system is fine for the most part. I just want them to buff the smaller types' Pokemon pools. Maybe move some of the types around a bit. Move Ghost to Darkness for example. But there's so few logical ones to do this with. Putting Flying or Bug or something into Lightning makes no sense. I guess smaller types are doomed to mediocrity. (That being said, this is a pretty good case for why not every type is seperate in the TCG. Can you imagine how pathetic Ghost or Ice decks would be with so few Pokemon of those types?)
The type system is fine for the most part. I just want them to buff the smaller types' Pokemon pools. Maybe move some of the types around a bit. Move Ghost to Darkness for example. But there's so few logical ones to do this with. Putting Flying or Bug or something into Lightning makes no sense. I guess smaller types are doomed to mediocrity. (That being said, this is a pretty good case for why not every type is seperate in the TCG. Can you imagine how pathetic Ghost or Ice decks would be with so few Pokemon of those types?)