It kind of annoys me how Matrix core devs never seem to acknowledge a fundamental risk in their protocol design: that untrusted third parties can trigger intensive computation on other systems (by creating complex state graphs).

It's not that there's no way to (sufficiently) mitigate this, but you do actually need to acknowledge that this problem exists, instead of fucking around in the margins with 'making stateres more efficient'.

As long as the graph complexity isn't forcibly bounded in some way, this is going to keep being a problem.