Yes it is a deep change. I think one of the biggest problems is the infinite-redundancy issue. Most protocols have no redundancy. We have unbounded lists of relays. I think 3 is plenty for any particular purpose. Given how many connections we already have to make, it is just too onerous to connect to all 37 of someone's outbox servers. If people want to list 37 outbox servers, clients should use the first 3 and optionally use more if those 3 are down, but beyond the first 3 nothing is guaranteed. Not every client needs to help users setup their relay lists direclty, they can pass users over to a different client or website that does it.