I think the quarter inch seam is mostly about bulk. It's no big deal if you're doing simple squares, but if you start getting five or six or seven seams all intersecting at one point it can become a big knot.
I don't see any reason why you can't use larger seam allowances if you keep your block intersections "light". You might even consider double-sewing each seam for some extra ruggedness for the dog's quilts. Or go over it with a zigzag or tight serpentine stitch that goes over each seam, that could be interesting-looking.
I have 3 dogs myself, but mine are more interested in flipping the quilt up with their noses so they can get underneath, thankfully. They normally only paw at the quilt enough to find the edge, then under they go! I guess we keep our house too chilly, LOL.