1. Not all visual languages are the same, just as not all text-based languages are the same. The main problem is there aren't many in widespread use, and they tend to be quite specialized, so you might not find one which you're completely happy with.
2. Programs, or rather functions/procedures/subroutines should, with very few exceptions, be displayable on a single screen. If they are larger, they should be split up. This applies whether the language is textual or graphical. Moving graphics around should make no difference to how a dataflow program executes.
3. Yes, it's easier to develop a new text-based language, because so much research has been done on them, and you don't need to develop an editor along with the language. But there are hundreds in active use, which are constantly evolving. If you want a new set of features, you can add it to an existing language or create your own dialect. Visual code must have either a text or binary representation of the source which can be shared. It may not be human-readable but that's not the intention.
2. Programs, or rather functions/procedures/subroutines should, with very few exceptions, be displayable on a single screen. If they are larger, they should be split up. This applies whether the language is textual or graphical. Moving graphics around should make no difference to how a dataflow program executes.
3. Yes, it's easier to develop a new text-based language, because so much research has been done on them, and you don't need to develop an editor along with the language. But there are hundreds in active use, which are constantly evolving. If you want a new set of features, you can add it to an existing language or create your own dialect. Visual code must have either a text or binary representation of the source which can be shared. It may not be human-readable but that's not the intention.