Full towers normally offer some very unique tools and ideas whereas mid towers aren't known so much for that. As stated, Full towers are plentiful with space.
However, it's not quite an assumption that heat will be less of an issue in a full tower. with more room for the air to go, the pressure is lessened which can often throw off the flow design or require you to use more powerful fans.
Also as mentioned, full towers take up a lot of space.
And, my favorite, full towers alot more space for liquid cooling components.