what the heck does "turf out" mean? I have never heard that term... and you use it continually in your post...
ewwww.... just looked it up. That is not an appropriate phrase to use and I take exception to your continual use of it.
We removed some things based on discussion and analysis. If you don't like it, then add them back in via mod. We are not putting this back in or adding any new features at this point.
Decisions were made. You don't like them? Choose a different theme and/or add mods. plain and simple... we're not going to please everyone with every choice.
that covers the majority of your complaints.
For your other complaints...
well... for one -- this thread is not for reporting issues with 2.1 nor it it for requesting features... so, basically, your post doesn't actually belong in this thread at all.
For reporting bugs... your report is less than useful - even if it was reported in the correct place (which it is not) since you don't indicate what actual version you are testing on.
And as fort "you don't like this". that's nice... I can say "I do like this" and it has the same effect. We've made decisions as a team. Overall, I think they have been the correct decisions to move forward. There will always be folks who don't like the new development. That's why we continue to support the old version(s) for a long time after the release of the new ones. So, fine... you can continue to use 2.0.x until we release 3.0 and make 2.0 end of life.
Modifications like these probably won’t show up. I personally like SMF for me it’s the best free software for putting the own forum I just expressing my opinion about that what I don’t like in 2.1, new version seems to be truncated version.
So write me where I can report bugs except github or to ask for new functions to 2.1, because frankly I have no idea. For you it should be plain and simple that I’m testing latest version 2.1 downloaded directly from yours github.
It’s not like this that I don’t like 2.1 completely but I don’t understand some of yours decisions in relation to 2.1, because in 2.0 everything is simpler and it’s my opinion. Maybe I got used to 2.0 too much.
SMF 2.1 with such a slow degree of the development will come out probably at the end of this year or later what I don't wish you, and 3.0 in 2020.

Because it was difficult trying to maintain the menu in two separate places and was actually breaking the layout in some places as I recall.
And why in elkarte side menu is available? This software rose from SMF 2.1, so why there can do it and in 2.1 not? Side menu is more comfortable than pull-down menu.
We can look into this.
Thanks.
We've added dozens of additional integration hooks in 2.1 that will make it easier to add mods without actually editing the files, but it's not easy to write a system that would allow you to do everything without modifying files without rewriting most of SMF.
All right but do you saw how extensions are working in phpbb 3.1? There normally you’re sending the extension to the server and then you enable them, it isn't overwriting any files, you can disable them.
Spam prevention and user privacy.
I understand it, but you could leave this function only for administrators. At present on my forum I disabled sending emails for everyone expect me as administrator so if I want to send email to someone through the forum I’m just sending and this function will be missing to me if I’ll someday update my forum to 2.1.
I'm not sure exactly what you mean here...

You can modify the popup to display additional details if you want.
In what way? Where it is possible to modify popup?
This should be fixed now
Still it isn't fixed. Last modification 2.1 on github was 7 days ago and this bug here on forum I reported 10 days ago.
It never has been. You can use the center bbcode tag to accomplish this if you want.
Impossible. I added the text or links without no centering and it automatically is shown in the middle, it’s in 2.0 you can check it. So probably in 2.0 it was a bug that the added content automatically was set in the middle and in 2.1 you fixed it.
When you get a new PM, it will show up in the "My Messages" popup and you can click into the message from there.
Need to click into title of private message in order can go into this message to read or into the INBOX button and it’s a little bit annoying but I understand that it’s a popup but in my opinion it shouldn’t be in popup but it is only my opinion. In popup could be only alerts which informed about coming private message or of other notifications.
We like the ones currently in use. What did you have in mind that would be better?
In my opinion icons for: Support and Credits, News and Newsletters, End Admin Session, Features and Options, Anti-Spam, Languages, Current Theme, Themes and Layout, Modification Settings, Search, Search Engines, Members, Membergroups, Permissions, Registration, Warnings, Ban List, Scheduled Tasks, Logs they could be better, it is only my opinion, rest of icons which I didn't list they are better, look more professional they are prettier, I have such a feeling, that these icons which I listed are wacky. Because the icon with information in the color blue isn’t much good. Icon for news could be different, it can also be newspaper, but I have other vision for this icon. Icon of end of the session is gray. The icon of sprocket wheel could be, but in internet I saw prettier. The padlock for the spam is average. Generally speaking I have no idea why you used padlocks for the tab spam. The icon of languages is average. Icons for theme are gray. The icon for managing of modifications hasn’t anything to do with the modification, it looks like puzzle. The icon of loupe is gray, I saw better. The icon for the searching engines is gray. Icons of Members, Membergroups aren’t so bad but could be better. The icon of keys for Permissions is gray. What keys have common to Permissions? The icon for Registration could be better, this blue stick man is gray. Icon Warnings is wack, this icon looks like traffic lights, change it. Icon of Ban List is ugly change her. The Scheduled Tasks icon could be better. In drop-down menu you used smaller other icons, they are better than the ones bigger.
If you don't like it you can use another theme.
I spent a lot of time with this theme and isn't so bad, although could be better, it what on top of I don't like in curve2 it’s orange contour in My Community - Info Center somehow for me this color doesn't match to the blue color. And I really don't understand what you added icons up to at: Home, Search, Admin, Moderate, Members, Logout.
Go to Admin -> Features and Options and make sure the correct server timezone is selected. We did it this way because it's simpler.
I’ve set the right time of server in admin panel for whole forum and when I’m log on then the main clock on main page show a one hour to back. In my profile format of time I’ve set as default for forum. In Timezone is automatically set [UTC] UTC and it causes showing the hour to the back, but when I choose my region from list then the hour will be correct. If somebody will be want to put the own forum on 2.1 after installing software as the administrator will be has a set wrong time for his account. You should fix it, because for me it looks like the bug. It should working in this way that after change the time of the server for the entire forum to all users including the account of administrator a time will change on correct, because now it doesn't work in this way. In 2.0 it works correctly, if the time of the server of the forum is set on UTC all users will have this time, but when I will change the time of the server on correct then for all accounts automatically will set the correct time.