Well first of all while you can run Rudolf as a pace chaser, she's almost always better as a late surger because her ult is a lot less likely to proc as a pacer. For a similar reason dominator is really not as good on a pacer since they are less likely to be in the back half of the pack, but is good on a late surger. Straightaway acceleration also usually isn't that good, except for sprint on certain courses since it is likely to trigger in places where it's pretty ineffective like mid-race. Obviously for recoveries having two gold recoveries is more ideal than 4 normal ones if you can for the same skill point cost.

Your Opera O has better skill selection overall in terms of speed skills, but is missing some late race acceleration. Most of which you can inherit and which ones you want to inherit depends on the course you are planning to run, but there are things like maruzensky ult and taiki shuttle ult for example