Hi @LordHedgie and thank you very much for taking time to provide feedback like this.
Your post is huge and I’m currently focused on writing code that’s why I toke me a long time to reply, and I’m not even going to answer to all points yet, but I wanted to reply to you.
So, here we go for “the bad” part:
The lack of a true native app means no Android or iOS notifications, which is a major drawback. This isn’t an easy fix, and I understand that, so I’m not expecting change here, but there should be recognition that it’s one of the biggest downsides to Diaspora for a mobile user.
Notifications is something which is part of the web for a while now, we don’t need a native app for this. It was added to the desktop (I agree it could be renamed “Full”) version since diaspora* 0.6.2.0 released the 14th December 2016 (see this pull request). At that time, the polling time was set to 5 minutes, to avoid an important load to the servers. Diaspora* should have asked you the first time you opened the desktop version if you accept notifications, and should send you an android notification when you have a new diaspora* notification that happened less than 5 minutes ago as long as you have the tab open in your browser. If that’s not the case, it means either you initially refused notifications (please change the setting in your browser) or there is a bug, in which case we need to investigate together.
This feature has to be improved, first of all to be added to the mobile version, where it is needed the most, and to allow podmins to set the polling time they want. I set mine to 30 seconds as I have a big server for a few users, and it works well.
There are two versions of the website that can be accessed via mobile, “desktop” and “mobile”. Confusingly, the desktop version changes when viewed on a smaller screen, so it appears different than when viewed on a desktop. There is no clear indicator for a new user which is which, and switching requires pressing a button labeled “Toggle Mobile” but doesn’t tell you which mode you’re in. Yes, eventually I figured it out, but it’s not intuitive. Furthermore, the mobile version lacks much functionality - users cannot mention, vote in polls, block users, ignore posts, preview posts, etc. The desktop version seems to work flawlessly, but as I understand it some people find the text links too small, and others don’t like that it downloads full size images. I would recommend that the fully functioning version be default for new users. I also recommend changing the Toggle Mobile link to be more clear - I suggest that it read “Switch to Full Site” and “Switch to Light Site” or similar, making it clear what happens when you touch it. Calling the full version “desktop” is confusing, because it does not look the same as what is seen on a desktop, even if the underlying code is the same. Every new user I’ve talked to has struggled with this. Remember, for many users, the mobile version is the first experience they have with Diaspora, and providing them with such limited functionality creates a poor first impression.
The situation is like this because you arrived during a pivotal period for diaspora* front-end. It is only temporary and is a work in progress. Diaspora* had distinct desktop (working only on big screens) and mobile (the one you currently have) versions. To maintain two versions is more work, so we want to switch to a unique, responsive, front-end. However, with our limited resources, this takes time. So instead of not delivering anything for months, we started building the responsive version and shipping it part by part. So you now have a desktop version mostly responsive, but the work is not over (links are too small, for example), and a mobile version which is still available because it is way lighter especially looking at bandwidth usage. As the two versions are supposed to merge, the more the work progresses, the harder they are to distinct. But your suggestion to rename the “toggle mobile” link is a good one. If others agree, I’ll do that change, waiting for the mobile version to totally disappear.
Notifications are often repeated as unread hours after I’ve marked them read. I’m guessing this is a federation issue.
This was a configuration problem of pluspora and has been fixed by your awesome podmin David with the help of the diaspora* community
Diaspora needs block functionality. Right now ignore appears to prevent new posts from showing in your stream, and (I think) prevent notifications if the ignored person comments on something you’re subscribed to. If a person is really offensive, you should have the ability to see absolutely nothing from them (or ideally) “comment hidden” that can be clicked to view it). Users shouldn’t be shown comments from blocked users on other people’s posts - this will really become a very serious problem if trolls start using the network.
There are many topics open about this (ignore comments, ignore reshare, and already kind of a duplicate) so I will not answer in details here. But since the coming of the G+ users, I think this is the worry which was the most pointed, even if each time someone ask about this worrying to be harass, it never happened to him/her at the moment. It makes me wonder how G+ atmosphere was. Why everybody coming from that network is worrying about being harassed and ask for the tools to defend without even be faced by it? In the worst case, when someone is being abusive, ask your podmin who will warn, temporary ban, or full ban the problematic user. diaspora* is used by thousands of users for height years, we even dealt with terrorism from ISIS, and we successfully survived. Do not worry, people 
G+'s greatest feature was its Collections, and adding similar functionality to Diaspora would set it apart from other social networks. Basically, similar to tagging, posts would be included in various Collections each user made. You could subscribe to some or all of another user’s Collections. For example, I could choose to see all of Bob’s posts about mountain photography, but not see any of Bob’s posts about the Denver Broncos. There are many different ways I can imagine this being achieved, and I’m not suggesting that Google’s solution is the best one, but being able to selectively subscribe to some topics from a given user is an amazing feature missing from Diaspora. Of these suggestions, this is also the most difficult to implement. Aspects lets you choose how much to share with a user, but nothing allows you to choose how much of a user’s content you see.
This is something I have in mind for years and deeply think it is the most missing feature in diaspora*. Basically, custom streams, with “boolean expressions”: I want all posts with #diaspora but not #diaspora-dev from userX or userY but not userZ. Those are advanced searches, and we could create custom streams by pinning those searches. We really need to help users see the content they want to see, and they will choose it, as we don’t want to go the Twitter or Facebook way of automatically hiding / showing based on obscure algorithms. So to sum up: we want to build that, but it’s a difficult problem from both the UX and the technical point of view. I’ll work on the UX point.