Speaking for myself, right click dragging the map is the most usual way I move around the map, so much that I've actually disabled the ability of moving the view by hovering the cursor over the edge, as I find that way less user friendly than just dragging and having the additional issue that it might happen it will move the view when you don't want to, or you have to be careful not getting too close to the edges. I virtually never use, or should say I would never use, the arrows to scroll the map around, so I've just set them at speed 1, reserving it for rare precision needs related to taking screenshots (nothing about gameplay).
Beside right click dragging the map, virtually the only other way I ever move around the map is by moving around the cursor on the minimap with the right button pressed, and I actually almost never do this while I'm playing (it is more for watching the map while map or mod making, or taking a general look at it, particularly when looking at a new big map).
Yet, while having no doubt that is the best way of moving around the map when gaming, amongst all the available ones, I don't think that right click and dragging the map is really an optimal way to change the screen portion of the gameboard, especially in maps you have keeping doing that a lot.
I think this method has two main issues.
The first issue is that how much you can drag the map per movement is limited to the wideness of your screen, at least, resulting in you having to keep dragging the map, then returning with the mouse all the way back, then dragging it again, and so on, that is far from optimal, especially in very big maps.
The second issue (and this would be a point in favour of scrolling the board by hovering the cursor near the edges) is that doing that likely moves your cursor away from where you want to have it (and likely exactly in the opposite direction), obliging you getting it back after dragging, substantially having you making the movement, in the direction you want to go, twice.
I suggest, instead of the current "dragging" behaviour, having the behaviour that right clicking on the board, then moving the mouse while holding that button, keeps the cursor in the same position, on the screen, while scrolling the board view as per your mouse movement (factually something analogous to what you can already do on the minimap, but slower (as long as 1 pixel on the minimap corresponds to many more pixels on the board) and not requiring keeping moving your cursor to and from the minimap).
Alternatively this could be, especially initially, prompted by some other command than right clicking on the board, then moving while holding the button.
Side note, I don't think it is really useful having clicking on the scroll wheel doing the same thing already covered by right clicking. But, in general, I don't think the scroll wheel clicking is really a good thing to have, so I would assign just nothing to it.
