I love traditional Irish soda bread but I've never had it - or even seen it- with raisins. For me- that's the whole point of it - it has it's own unique flavour that isn't supposed to overly sweet. I also like the dense, sort of chewy texture (that's my favorite part) and I think anything added such as raisins or carrraway seeds would detract from that.
The simplicity is what I most like about soda bread. I tried to make it once, but couldn't replicate the texture - but I was able to find a market that carried it and I'd buy a loaf every few days and just eat a slice plain or with butter.
But if you like raisins - I'd put them in. Unless someone is a real purist (like I am
) I don't think they'd mind. In fact the rest of my family doesn't really like soda bread because it is so plain - so maybe adding raisins or carraway seeds would make it more appealing to more people.