I still say no to countdown ._.

Actually I don't like countdown too. Well, if other mapper think so, we can restrict countdown but if not, we can't restrict that.
To decide this, I think we need more opnion.

The worst case for drumroll examples.

Ever.

Hmm, let's see...

Countdown: Anti-estethic to see and to hear in osu. And that means NO countdown!
Slider Velocity: Generally for Tv sized Taiko maps using a x1.30 multiplier is good, but I think it's better to let mappers set them for themselves...
Finish Notes in 1/4 streams: uglyuglyuglyUGLY! It doesn't have much sense, perhaps.
Kiai Time: For song choruses is fine, but even for this stands all to mappers's choice. Even because some taiko original songs from Namco games abuse of Kiai time for over half map (Examples: Taiko Go!-Go! Godaime Opening song or Okashi Deka no Uta)
Note Combo: I personally love using particular max combo numbers as a continuation to Namco's, but for the other mappers can be good enough to let them choose how many notes insert (just, don't fill 1-minutes song with an exagerate number of notes... @.o
Drum rolls:Meh, it's good for me, until (as said before from others) don't stack 4-5 sliders on a row, or a serie of sliders which changes continously speed...
Spinners: there isn't a minimum/maximum value for them. Just, don't let players insets TOO MANY on a row, even if some exeption are seen on Taiko games (see Speed King)
Overlapped notes by BPM Changes: It's fine; just leave a little zone with no notes between BPM's changes from slower to faster; and vice versa, from faster to slower isn't needed a zone without beats...
Break Sections: If someone wants to map something in Taiko mode, maybe he/she must stay away to use break zones, in my opinion...
Measures and Barlines Maybe for specific maps, skilled guys with a storyboarding experience can set a particular Taiko drum for their songs! I know it's hard, but maybe by encouraging people to try this artistic road, players would enjoy better playing that map...

Countdown: What is wrong with a countdown?

Slider Velocity: I believe this should stay at 1.4 for most songs, unless the song has a very slow bpm ( Like under 100 )

Finish Notes in 1/4 streams: No.

Kiai Time: I think kiai should be regulated to some point, because not every part needs kiai. Maybe once or twice a song is fine, depending on length of song and how many times it play a chorus.

Note Combo: I think mappers should be able to have a combo as big as they like, I know its in namco tradition or something to do this, but I guess it could fall into terms for the length of the map. (Like a 2 minute song shouldn't have 100000000 combo. lol)

Drumrolls: Ends and starts should be at least a half a measure apart.

Spinners: Spinners are fine in a good moderation like kiai and sliders.

Overlapped notes by BPM Changes: Someone fill me in on what this means >_>

Break Sections: I wouldn't see a problem in this as long as there not very long breaks, or again, depending on the length of the song. If a map is 2 minutes you should map the whole thing, but if its, lets say 4 minutes, mapping can get a bit repetitive.

I didn't read everyone else's post because i'm in a bit of a hurry, but I will keep an eye on this.

Depends on how annoying the hitburst is, we should try and keep it to the normal taiko skin though.

OK,so here's my two cents....

Countdown: Eh it doesn't affect gameplay,so I don't mind having them.(heck,my taikomaps have them too)
But a big no-no for authentic maps.

Slider Velocity: Keep it at 1.4,unless it's absolutely necessary to use another value.

Finish Notes in 1/4 streams: IDK,it depends on the song itself.(sometimes it sounds better that way)
But keep it at a minimum.

Kiai Time: Depends on the length of the song...but for regular length songs,perhaps one or two is enough.

Note Combo: Once again,depends on song length.For regular length it's better to keep it under 999.

Drum rolls: Unless it's authentic or on Kantan/Futsuu,no drumroll spamming.

Spinners: Not too much,and no having notes immediately after spinners.After all,spinners cover the whole screen.

Overlapped notes by BPM Changes: NO.Overlapped notes are impossible to hit.

Break Sections: Since breaks or the lack of it won't affect taiko gameplay...I don't mind having them.

Custom Hitbursts: I'd rather not have them.

Measures and Barlines etc... IDK about this...

Countdown: Seems quite lot's of mappers don't mind whether it's turn on or off... Should we say 'avoid countdown', or just set no restriction about this?
Slider Velocity: Lots of mapper think 1.4 is fair, but we don't need to force it. Let just say 'recommend' it.
1/8 notes: lol seems everyone missed this one. Anyway it needs to be avoided.
Finish Notes in streams: Seems most mappers don't like this. Anyway we need to set exact limitation, as mappers sometimes set SV other than 1.4.
Kiai Time: Some said about some criteria. See above.
Note Combo: Seems some mappers like certain number, but basically we don't need to regulate this, right?
Drum rolls: Of course everone don't like spamming...
Spinners: ^
Sudden change of Scroll speed: We need some exact limitation of this. We got some opnions already...
Overlapped notes by BPM Changes: We don't like this.
Break Sections: Seems it's not that necessary in Taiko, let's say... avoid this unless the song is long?
Measures and Barlines: Need to add uninherited section if it's needed

Hmm... any suggestion?

EDIT: subject changed.

Looks fair. :3

Still need more opnion. This post should be more active than now.
*send some invitations to other mappers*

Countdown: I prefer not to use this thing orz
Slider Velocity: Unless yours is TaikOsu, 1.4 is the best speed imo ;_;
1/8 notes: Except Hataraku2000 or else crazy songs, It doesn't need to be overused orz
Finish Notes in streams: NEVER except OOdain...
Kiai Time: As 'DON'T CUT', do not cut Kiai Time while that's highlight part ;_;
Note Combo: Maximum 999 is fine on TV-size or the songs which are up to 2min. Else, unlimited orz
Drum rolls: Doesn't need to be overused but... WTF YMCK...[Muzukashii...]
Spinners: ^
Sudden change of Scroll speed: I dunno but if rhythm distance is too short, it should not be used orz
Overlapped notes by BPM Changes: NEVER.
Break Sections: If TaikOsu, allow :3 If Taiko-only? I dunno ;_;
Measures and Barlines: Depends on song's data orz



:3?

Countdown: Depend on songs
Slider Velocity: no restriction imo.
Finish Notes in 1/4 streams: NO unless obviously slow (e.g. BPM 100
Kiai Time: similar to solo diff, except those created by namco
Note Combo: NOOOOOOOOOOOOOOOOOO
Drum rolls: I suggest at least drumroll should at least last 1 beat, also dense rolls should be avoided (I don't know why there's 1/8 drumroll sometimes...)
Spinners: NO restrictions
Overlapped notes by BPM Changes: Overlapped notes are absolutely unrankable. At least no two notes should be so near, not even due to BPM changes.
Break Sections: No restrictions to break or not, but no need to put break section on breaks, TaikOsu of course allow~
Custom Hitbursts: I closed that function ._.
Measures and Barlines etc... <- same as solo
1/8 notes <- NO way for fast songs, also applied to 1/6
Sudden change of Scroll speed <- Avoid whenever possible.




More about SV: 1.4 would not be a good choice for every song, while we should never try to force taiko map in osu to become another namco demonstration, and I used to start with 1.6 or 1.8...

Authentic is shouldn't be our standard, show our creativity under a reasonable way will be fine enough

1/8 notes should be restricted to songs with BPM of <170, and never used on anything but the top-level difficulty.