Apple's knowledge base has some of the harder to spot removals although they do not list all of those discovered by Users here:
Updated Check List
New Pages 5 added, removed or altered features:
Added
+ Right to Left text
+ Single model templates. No More Word Processing/Layout templates
+ Share outside iCloud
+ Phonetic Guide for Chinese & Japanese
+ Custom Template names can be changed inside the Template Chooser by right clicking
+ Custom Templates can be deleted inside the Template Chooser by right clicking
+ Text language is detected automatically
+ Collaboration
+ Unite/Subtract overlapping Textboxes
+ Unite/Subtract overlapping Shapes
+ Extra Shadow effects
+ Double click to mask image
+ Instant Alpha target zoom
+ 16 more languages
+ Multiple T.O.C. and can have them for each section
Removed
Select non-contiguous text
Outline view
Customizable Toolbar
135 templates
Capture pages/sections
Drag reorganize pages
Duplicate pages
Delete page
Manage Pages
Subscript/superscript buttons
Select all instances of a Style
Retain zoom level of document
Facing pages
Layout Margins
Media Inspector links to iPhoto library on external drive
Media Inspector links to Aperture Library
Styles Drawer
Merge Fields
Drag and Drop VCards
Default Start Up page
Vertical Ruler
Drag out Vertical (and Horizontal) Alignment Guides
Style Function key shortcuts
Bookmarks
Hyperlinks to external documents
Images within Tables
Mathtype Equations/Formulae within Tables (and other Objects?)
Grapher Equations/Formulae within Tables (and other Objects?)
Import Styles
Clean Import of older .pages formatting
Full User Guide (there is a short online guide missing many features)
Search Sidebar
Open Type features
Textbox linking
Background Object selectable
Storyboards
Text to Tables
Tables to Text
Tables in Headers/Footers
Export to .rtf
Import from .rtf
Multiple Comments view
T.O.C. clean numbering
Selective formating in Character Styles
Insert File Name
Search in Media Browser
Bullet points in comments
Search comments
Two up view
Paste and keep style
Custom Auto-correct
Find & Replace special characters eg paragraph returns
Auto-Dates on opening document
Speech to Text
Format Bar
Open Pages '08 documents
Headers in Tables
Sync with iOS6
Auto capitalise sentence start
Open .doc files
Roman Numeral Page Numbers
Character count including spaces
Import linked Numbers Charts
Styles including bulletted lists
Recent fonts at top of Font List
Page of Page Count at foot of Window
Full Screen background color
Font name matching between OSX and iOS
Copy/Paste from Pages '09 to Pages 5
Certain Fonts eg WingDings
Saving onto Windows server
Status bar
Drag out inserted image to Finder.
Uninstall permanently
Rotate Tables
Rotate Charts
Display non-printable margins
Group pie wedges in Charts
OSX Spotlight Metadata
Custom number formats in charts
Table fills
Copy Paste of citation text and footnotes
Change tracking for non-body text
Open Recent from Template Chooser
Opentype features
Copy/Paste Thumbnails across documents
Insert Filename
Altered
↪ Pages '09 files saved from Pages 5 in Maverick are not protected by a simple name change eg (converted appended)
↪ Pages '09 files previewed on iPad via iCloud are irrevocably converted
↪ Update is missing for older installations, Apple is reportedly working on a solution via a redeemable code or update on their Support Download site
↪ Wrap methods have been cut back severely
↪ Documents reconverted back to Pages '09 lose all template information
↪ Language set under Edit > Spelling and Grammar > Show Spelling and Grammar now document wide
↪ Subscript/superscript text is now a convoluted route Gear > Advanced options > Baseline > Subscript/Superscript
↪ Headers and Footers appear to be multi-column
↪ Text is not wrapping in Footers
↪ New file format (but still .pages?) not backwardly compatible
↪ Page numbering method changed
↪ Custom Templates are now stored in ~/Library/Containers/com.apple.iWork.pages (a package)
↪ AppleScript Library for Pages 5 has changed with many classes and commands removed which indicates how the feature lists have been slashed
↪ Character Styles are in the Text Inspector under Bold, Italic etc
↪ Tabbing within Table cells appears to be inconsistent, tabbing internally with numbers.
↪ Drag and Drop text only works with .txt files now
↪ EndNote plugin is partially broken unable to cite in footnotes and problems with in-text numbering
↪ List options are now in a pop-down menu in the contextual Inspector
↪ .doc no longer supported, only .docx
↪ Text highlighting is now under Format > gear icon > Advanced Options > Character Fill Color > Color
↪ Mail Merge has changed. Some people are reporting links not working despite Merge is still in the Insert Menu
↪ Merging Table cells is now: select the cell/s > Format > Table > Merge
↪ Unmerge cells only undoes the above
↪ Table Borders is now: select the cell/s > Format > Table > Cell > click on triangle > choose
↪ Quicklook preview of Pages '09 files in Maverick is reportedly buggy
↪ Layout Breaks work differently. You select the paragraphs you want as an exception and then change the column numbers. Currently can't find how to set before and after spacing or margin inset btw This is a totally undocumented and hidden procedure.
↪ Word Count is now Menu > View > Show Word Count
↪ Bookmarks are missing in Pages 5 but are still retained if exported back to Pages '09
↪ Bolding requires clicking on style and checking Emphasis
↪ Save as… is back