Mastodon... it's a platform, not a single entity that I can use.
That might be the tradeoff that has to be made. Pick a Mastodon instance whose administration you trust not to screw you over. If they do you can move to another. If you go with a single entity, you're going to be stuck when they mess with you. Like with Twitter.
A strictly chronological timeline is only available via third party apps.
Also, now the "content you might have missed" stuff is showing up in Notifications and whoever thought that was a good idea?
This is really what Mastodon needs, a solid sponsor. I want to use it, but the loose federation model without core instances that have a critical mass of users makes it hard to commit to. In Japan, when Pixiv sponsored Pawoo, the Mastodon usage shot up, I think that's still one of the biggest instances worldwide right now.
Also, Mastodon needs a good Mac client. I would pay for both that and to support a general Mastodon instance backed by someone with name recognition.
Twitter offered a base service that was great and they are now constantly removing features (no chronological timeline, no access to polls for 3rd party apps, now no streaming for 3rd party apps). A few days ago on HN we were talking about Mastodon but I don't see it replacing a Twitter as it's a platform, not a single entity that I can use.
The best scenario I can imagine would be to see the teams behind Twitterific and Tweetbot creating a Mastodon server and offering me to switch in the app in the coming months. Twitter is screwing us because we are, as users of those apps, the 1%. And I'm quite sure that the people I follow are also part of the same single percent.
To The Iconfactory and Tapbots: make me pay again, ask me to pay a subscription, I don't care. But screw Twitter, they treat you (and thus us) like garbage, make me switch to something offering me a better experience and that is guaranteed to last. Is posting tweets from my account through your apps still free? Then offer me the possibility to send tweets when I send messages on your new platform + a weekly message to send to my few followers that they should also switch.
Twitter is gonna apparently kill you at some point anyway, letting your users see a stream ordered by a shitty IA and with 1/3 of ads. So please, let's fight instead of slowly dying.