@eesty thank you so much for posting feedback here, it certainly helps us.
I did want to quickly address the various points here:
This pops up from time to time. A very strong position we have held ever since the project started is that “we will not add pagination”. At a fundamental level, if pagination is a must then Discourse is not a good fit.
Improving the experience though is on the table, things like allowing users to see bookmarks in the timeline, and fancier timeline controls are things we think about.
Though we will certainly not be adding this to core, amending post actions is completely doable in a theme component if you must. But keep in mind there is an aspect of “we must have MacDonalds” OK… “here is your unhealthy hamburger” to this.
This is something we do work on a lot (and did work on for our current release). It is hard to provide the huge amount of features Discourse has on offer with a very tight performance budget. We try to though, and we definitely made some improvements in the “user with tons of posts” department. @tgxworld even worked on the “giant topic” problem a bit a few month back.
There is a fundamental issue though, to get all the features Discourse has you are going to need more server resources than traditional dead simple php forums.
@neil recently spent a fair amount of time on this ad problems, I would be very curious for any specific reproducible issues. We want to improve this.