I have a first gen framework and I really like it. Having the ports behave differently on this AMD does seem a little annoying but I guess you'd get used to it.
I think it's an alright compromise. I rarely move my expansion cards around. I use four USB-C cards and sometimes swap one out for a storage card that has Windows installed on it.
I also don't move them often, it's interesting they weren't able to get all 4 the same though. I haven't read anything that actually explains it. I guess the CPU can only handle that configuration.
The Ryzen 7840U and 7640U, by specification, support 2 USB 4 ports and 2 USB 3.2 Gen 2 ports.
So it seems that's just a limitation by the architecture.