No auto-complete support for new block state syntax

Thanks for reporting this - the changes have been outlined to some degree in the 1.19.70.21 Preview Changelog:

• https://feedback.minecraft.net/hc/en-us/articles/12739185905933-Minecraft-Beta-Preview-1-19-70-21

Here are some additional examples of the syntax that might be useful, particularly when using the fill command to replace blocks:

/setblock ~~~ green_wool []

/setblock ~~~ wood ["wood_type": "oak"]

/setblock ~~~ coral ["dead_bit" : true , "coral_color" : "blue" ]

/setblock ~~~ coral_fan ["coral_fan_direction" : 1, "coral_color" : "pink"]

/setblock ~~~ wool ["color": "blue"]

/fill ~ ~ ~ ~5 ~5 ~5 gold_block [] replace air

attempting to use /fill ~-5 ~-1 ~-5 ~5 ~-1 ~5 air 0 replace grass when previously 19 or 20 hours ago it was a valid command, specifically when plugging that into the chat box, its the 0 part that is apparently invalid, and trying any other way from any other game version or by example is also invalid

massive bug here when java minecraft doesnt need to use the block state!

With every game update I am wondering what they will mess up/make worse, and this time it are the commands.

There is no color options for wool and concrete when using the fill/replace command, also the number values do not work anymore.

Why change a system that works perfectly and what was easy to use? 

You express my frustration well. The 50 block limit has been recognized as a bug with fill and clone for months but no fix. I have been working around that one while waiting. Each release comes without the fix even thought it is statused as fixed. Now this bug with fill has no workaround. Will this take months to put it back where it was??? Sorry. Frustrated is an understatement.

How exactly is this not resolved as intended? The changelogs clearly stated that meta data values are no longer allowed, and block state syntax is now the only accepted syntax.

grass [] hollow (in the newest preview, the block state argument can be left out entirely.)

This is not a help desk, it is a bug tracker; for questions consult the wiki, reddit or just google.

Dhranios:

How exactly is this not resolved as intended? The changelogs clearly stated that meta data values are no longer allowed, and block state syntax is now the only accepted syntax.

Just because an issue does not exist in the latest Preview version does not mean the feature is intended to be broken in the current release. In this case, the bug really is that new syntax was implemented and completion suggestions were not. This gives the appearance in-game that the commands are just broken, and leaves players with no in-game way to figure out how to get around that.

I found the new syntax  

https://wiki.bedrock.dev/commands/block-states.html

and the full list of aux values

https://auxval-to-blockstates.netlify.app

For those who just want to replace blocks:

After you put in the block you wanted to be placed / replaced with, you just put [] in without a space and then replace etc...

That looks something like that:

/fill ~ ~ ~ ~ ~ ~ grass[]  replace ice

Then it should work as you want it. 

Air doesn't have a block state, and you would just leave the brackets blank.