Personally, if she is walking fine I would think that it is okay to switch her over. I would go for the tennis shoe as they are more stable and will support her ankles more. Besides, at almost 2 years old, she is going to be running a lot outside and she is going to need the padding from the ground. You can feel the rocks and hard ground through the soft leather. Protect her feet--that's as good an argument as any.
I went to stride rite because my daughter has wide feet and I couldn't find shoes anywhere to fit her. It is a bit pricey, but the shoes are made really well. They do have sandals there that offer support as well, but my daughter isn't walking by herself yet. Once I put the tennis shoes on her, she really started working on walking. I could tell that she was more stable standing up and I'm sure she feels the same way too. My son could fit into everything but I always put him in tennis shoes as well. My theory is: if I'm not going to buy crappie shoes for myself, why would I buy them for my children, especially when they are growing and learning to walk?" I don't buy super expensive shoes-can't afford that. However, I buy something that will last and that I can pass along to someone else or save for my daughter.
Good luck with the debate.