and if the bases were, oh lets see, square perhaps like the DnD grid system.
This complaint has never made an ounce of sense to me. Why should it matter if the edges of the base don't perfectly align with the grid lines? So long as it fits within the grid itself, what's the difference?
The only difference I see is that round bases are BETTER than square bases. How? Because you can position the miniature in any direction you like, without the corners of the base overlapping the gridline.
This matters when you have a bunch of miniatures squished together, and they've all got something or other sticking out beyond their base line. Whether it be a tail, a weapon, a cape, shield, etc. With square bases, if you butt two of those guys together, then there's only so many ways you can face a character to get them to align next to each other without causing any problems. And if you don't, then you gotta push one of them off the grid, which means that you gotta push the next miniature off the grid, etc, etc, etc. Before you know it, you got a slew of miniatures which're all straddling two grid boxes, rather than staying neatly in their own grid boxes.
This usually isn't an issue when there're a few figures on the board, but when there're a lot of people fighting in really cramped quarters, trust me, it becomes an issue! Eventually it's gets to the point that you just have to take out the miniatures and replace them with pennies, which defeats the whole point of HAVING miniatures to BEGIN with!
Which is why circular bases are better than square bases. Because you've got more than just 4 directions in which you can point a miniature, and allow for him to fit next to another miniature who's got any number of protrusions, and still stay within the gridline.
But even ignoring all the benefits of round over square bases, I still don't get the need of some people to have their base edges align perfectly to the grid lines. What is it, some kind of psychological need to see geometric shapes go together? It makes no sense, and I have yet to see anyone explain just WHY it's so important that the bases be square, beyond saying that "They have to be square because the grids are square".