Upgrading to MT 4

I'm upgrading this blog software to Movable Type 4, probably breaking a few things around :p. A few thoughts while I'm working on it (this post will evolve as I dig in)...

N.B. I'm working behind the scenes first. And this is still a beta version (4.0-rc1), but my little finger tells me that those who are waiting for the production version won't have to wait too long now ;-).

Things I'm really happy with...

The installation assistant is a breeze (with one quirk, see below)
Pages, using the blog templates, yeah!
Better file manager
Much better user management (better granularity at rights, but more importantly one can really build a multi-blogs multi-authors farm with this)
Better templates management, code, engine (gotta love MT tags!)
Much better default templates, and choice of designs and layouts out of the box
Long rebuilds seem broken down into several short perl processes, ~~so they don't time out on hosts that impose CPU time limits on process execution (like TxD)~~ [strike that, my first big rebuild got killed in the middle of rebuilding Category Monthly archives (what's that???) but I was able to resume by reloading the progress pop-up], they also display a nice progress bar

Things that show it's still a beta...

The drop-down menus have an annoying habit of not disappearing automatically after they lose focus
Some template tag mysteries in the header of the Main Index
I get a server error 500 when trying to display the System Information
Sometimes an unhelpful error message pops up, saying "an error occurred"

Things I'm really unhappy with...

The Rich Text editor is ~~crap~~ errr, weird... (see below)

I wonder why...

The Learn more about installing Perl modules link is not shown on the first screen of the Requirements Check of the installation assistant. Currently it appears only after you have successfully passed the check for required modules, which means you won't get a chance to see it if you're missing a module, since it's not even listed on the error screen (too bad!) -- Remember: $ sudo perl -MCPAN -e 'install <module>' is your friend!
There is a <$MTEntryTrackbackData$> tag on the default Main Index template for each entry. Apart from doubling the weight of the home page with useless junk and making spammers life easier in collecting TB links to hammer, why on earth do we need Trackback data in there? I recommend removing that tag from this template.
Some functions of the Rich Text Editor do not work in Safari (like lists, link, quote). It appears to be working better in Firefox, although...
The Rich Text Editor produces tons of ugly fucking code behind the screen, especially when using Safari. So it's an old-school editor such Midas, only a slight improvement over WYSIFUC in the sense that it hides it from you (unless you select "none" in the Format menu or "HTML Mode" and scream in horror at the FUC it generates, like ... instead of ...!). For example, on Safari it generates a DIV per paragraph, while on Firefox it just spits out tags or cosmetic or tags (not even , or or tags, mind you). So, three years after my FUC rant, authoring pain has just cosmetically improved but at what cost (producing tons of cosmetic-ridden tag soup like it's 98 again)? Those who have carefully designed their blog to valid XHTML/CSS web standards will see it become invalid the second they use the Rich Text editor in MT 4, you've been warned! I'm losing hope to ever see a decent open source WYSIWYG editor for authoring web content that follows modern web standards (yes, I know that HTML4 is a standard, that's not the point at all)... Sigh! [Hold on, Laurent tells me that this behavior was present in earlier betas but he doesn't see it in 4.0-rc1, I guess I need further testing]

I wonder how...

To remove or edit a link in the Rich Text editor? Looks like you have to delete the whole text with link and do it again, very annoying.
To migrate the database from MySQL to PostgreSQL? I tried what looks the simplest path (export/import) but the MT text backup doesn't transport tags!
To disable / prevent build of unnecessary category archives? It looks like the default install builds everything that's listed on the "First Widget Manager", including very time-consuming stuff like Date-based Category archives or Date-based Author archives (quite useless on a single-author blog like mine), although none of those are listed anywhere on the live blog and that widget is not active. In other words, where are the Archive Mapping preferences that allowed to define what archives get built in MT 3.x?
To distinguish photos within images? In the default templates, MT4 displays as "Photos" any image file you upload, but you might upload images to illustrate posts that you don't want mixed and displayed along with other photos.