For me it looks very weird and defeats the whole purpose of Matrix. I mean: it was designed from the ground as a federated network, similar to E-mail. Turning it into a completely different topology will not end well. If they want a P2P client, they should design it from the scratch. Otherwise it'll end up as a bunch of hacks glued with tape.
It wasn't designed exclusively as a federated network, tbh - we've been planning for P2P since pretty much day one; https://matrix.org/~matthew/2016-12-22%20Matrix%20Balancing%... is a talk I gave in 2015 when Matrix was less than a year old on our plans to go P2P.
Personally, I think it's really nice that in P2P Matrix precisely the same client-server API is used as for normal Matrix, so all the work that goes into the Matrix client and E2EE etc is preserved without any changes at all. Instead, it just talks to a server running on localhost, which then replicates traffic around over the P2P overlay (in future using store-and-forward servers if the target server is offline). It's really not a bunch of hacks, thanks to Matrix being architected to make the replication transport & protocol pluggable from the outset.
