As I've said before, in my opinion not every character has to be all-singing, all-dancing, appearing in just the right amount of scenes, reacting with perfection to every situation. ("Why does character x do this when we all know she should be doing y??")
People are also very quick to call someone a spare part when they haven't had a storyline for a few weeks. I actually enjoy the fact that soaps have a mix of characters, none of whom are perfect. Dot isn't my favourite character, as far as older ones go, I love Patrick, but I do enjoy Dot's scenes. She is actually in a great situation for her age. She has a lovely house which will be worth a huge amount, and has lots of family and friends.