I also have this same issue. I have a theory about the cause and would like to find out if any of the admins have the ability to modify my account. As @David Somo mentions this occurred for me after an updated (1st Cliffs and Caves I believe). After the update I have factory reset my XboxOne 3 times and reloaded the game a few dozen etc. As with the other reports my slowness happens if I am in a world or not and if I leave it in the menu it will freeze as well. Also I can do the unfreeze by opening the Xbox menu and closing it, which will give me a few seconds in which to do something before it freezes again.
In my profile I have several worlds that are completely inaccessible to me as when I attempt to load or modify them (even to delete) I receive an error on sync. One of my world's is my son's (who is 4) that is filled with just junk data but had ballooned to about 500MBs in size. After the factory reset I am unable to delete this or any older worlds from my profile. My working theory is based on a problem I have dealt with in the Active Directory arena. When a person logs into a new computer or server their roaming profile must be transferred to the workstation if they store dumb things like music or movies in their profile it can case the profile to be a few GBs in size and the login to the machine can take a really long time.
If the profile fails to load in windows it just gives you a temp profile, but my theory is that a background sync may be running while I am in the menu or playing the game and it is failing to download this massive world(s) in the profile and is resulting in poor performance. If at all possible can someone go into my profile and delete any world over say 50 MBs just to see if this will work to resolve the issue? I would do it, but I get the sync error on any of the older worlds.
If needed I can provide video of the freeze, with my phone because if you take it with the Xbox capture the world still works fine, but you are just standing still.
Reply from @unknown:
The bug tracker's purpose is to gather bug reports and additional information about the bug. The staff here are volunteers from the community. We do not even have access to your Minecraft account, let alone your Xbox account or your personal file storage. Literally all we can do is forward the bug information we manage to the devs, This is not a customer support site.
Please familiarize yourself with the bug tracker Guidelines and FAQ, which explains how you can use the bug tracker. If you haven't, I would also recommend reading the previous comments.
Thank you Auldrick, sorry for the confusion. I was sent here by Mojang support. They led me to believe that this was something like and 'escalation queue' for very difficult issues.
I understand it is being worked on, I have now read all comments on the thread. Thank you for your help. I will attempt to make a new account and link it as I don't have many purchases or worlds I care about.