Though I don't entirely agree with the reasoning, the Ring/Band of Callous Aggression was removed on the grounds that it is possible to have two better rings without being dependent on drops (Runed Band of the Kirin Tor and Ashen Band of Vengeance), while the Dexterous Brightstone Ring is easily available through Emblems of Triumph.

Forgive my noobish question, but I couldnt figure this out by myself. Why is the combat sheet, after having entered everything correctly, reporting my chance to miss poisons at 0%, when I am at 252 hit rating with 5/5 precision and no racial passive as undead?

If you have Imp. FF / Misery on the target, you need just 237 hit rating to be spell hit capped.

Poisons are spells, so poisons hit cap is the spell hit cap.

I found an error! In the Buff section on the settings sheet, it's stated that "Ferocious Inspiration" is from feral druids, while it actually comes from beast mastery hunters!

This is my take on it, so by no means take it as Aldriana's

These sheets are intended to be tools to help people doing end-game content do the best they possibly can, so it pretty much comes down to keeping the sheets as streamlined as possible for the majority of the intended user base. Keeping old gear clutters up the item selection process as well as bloat the sheet more than needed. Having to add functions to show/hide these old items to cater for what is essentially the minority of the intended user base isn't exactly a good use of time and resources that could be spent doing other things to improve the sheets.

If you're not doing the end-game content, there is no real reason for you to update to the newest sheet and re-add items to it unless there is a significant change in how a rogue mechanic works, etc.

I do believe that anyone using the spread sheets should be invested enough in this forum community to not just download the sheet and follow it blindly.

I can't help but feel that a reference for what version includes which pieces of gear, class mechanic changes or bug fixes (if there even have been any recently) would be a good addition.

New players join the community daily, some of these are just new rogues seeking to embark on the knowledge available on this board. Just because a rogue is below the current standard (or tier) of gear, does not mean they are inherently uninterested in their performance. I don't mean to imply that the sheet should have a clutter of useless items, perhaps some easy median would be possible. Such as a option to condense the gear listed on the sheet to what's relevant to end game.

I also know Aldriana is busy these days so then again it may not be a worth while venture for the current sheet.

I have unhidden the calcs sheet so I could enable the 4pc T8 on the mutilate spreadsheet but the sheet isnt modeled for a rupture rotation. Does anyone know if there is a simple way to add it, possibly cutting a formula from the combat sheet or something of that nature? Or should I just wait for the 3.3.3 sheet to come out?

A simple way? No, not at all. You'll have to wait for the updated sheet.

The other option is to dig up an old mutilate sheet and update it for the other changes that have been made, such as the HfB nerf. Results from spreadsheets hacked like this and from the simulation sheet show that adding rupture is possibly a marginal increase from a personal DPS standpoint, but from a raid DPS perspective a rupture rotation with Glyph of Rupture is behind the standard 4+ envenom rotation with Glyph of Tricks of the Trade, even if you're just using Tricks on a tank, let alone on another DPS.

Basically, it's not really worth finding a sheet to hack, and I wouldn't hold my breath for it to be added to the official mutilate sheet.

Also remember a lot of fights in ICC are heavy movement so spec'ing/glyphing for Rupture might not always b the best thing.

Marrowgar - Entire bonestorm phase spent not DPSing
LDW - Running from boss to adds + Adds
Gunship - Adds likely wont even live through a full Rupture
Putricide - Helluva lot of movement
BQL - If you get really unlucky with Pact + Spin phase
Sindragosa - Helluva lot of movement
LK - Fair amount of movement + Valks + Defile + Vile Spirits + Phase changes

Plus, I forgot about Aldriana's post that the Rupture model wasn't the greatest so it's fair to say it isn't entirely accurate and likely too high, so the real numbers will be lower.