@jancsika That is very probably true, but Pd was conceived (I believe) primarily for audio and composition, where audio should be confined to a +-1 y range (hence a new array has such limits). Vanilla objects that "shipped" with the first releases have -resize flags for the x range, and data structures have setsize which can be automated to fit requirements.
Of course that was necessary from the outset, as drawing millions of points will (as far as the user is concerned) "hang" Pd.
On the y axis though this is unnecessary as there is only one point, and it "should not" be outside the +-1 range........... unless there is a bad mistake in the patch then working with audio "y" is unlikely to be much outside that range.
It is true that arrays and graphs are not very easy or pretty. An abstraction with auto-range and all the x-y ticks in place would be great, but you would end up with a graph that is constantly changing, as it cannot "know" what is going to be thrown at it........ and so you would have no idea what you are looking at. We have to do some of the work ourselves, and we were just given the basic tools to do "anything" that we wish..........
To view only a part of your data you would have to load only that part into the graph (using -skip and -maxsize)..... that is true. A movable window would be a useful tool (project for tomorrow!).
Is someone trying to build a daw again.......... there are very good free daws around already!
(P.S. you can stop the drawing outside the graph by burying it under 2 levels of gop.)