Mon mentioned alternative pads that are bit more comfortable and other mention other pads they used. I don’t know in particular about the aivas but generally you are correct that deeper can result in more soundstage but can also recess bass or other frequencies. Different more breathable materials usually add to soundstage as well. What is it about the pads that you don’t like?
Pads can be tricky overall. There are some headphones that always sound best with their own pads like the sennheisers, and those that are more forgiving with pad swaps. Also, there are those headphones that seem like they were made for other pads. It can be tough to gauge what is best as by reading, as with all audio gear, what others say it’s hard to tell what you will like as all tastes are different.
I would say that for most headphones, if you like the signature, it’s best not to mess with the pads, but some things like comfort are hard to deal with. At the same time experimenting can be the fun part of headphones as well so it’s always worth trying. Brainwav pads are almost always guaranteed to offer more comfort that most pads, and are a safe but since they are usually inexpensive and you can always return them.
Just know that, as I’ve read so often, it seems that most part swaps end with being swapped back since more often than not, the stock pads will usually be best sound, at least from my experience and what I e read. However it’s always worth a shot! And maybe the added comfort is worth the change in sound.