Earlier quoted context omitted.
Vim doesn't need multiple cursor support. Train yourself to think in Vim—you're editing text and words, not moving a cursor. Macros and global replace already do what you want.
Macros and global replace are substitutes, sure, but they're not at all the same thing . And while I'm no vim wizard, I have used it as my main editor for 4+ years, and have a 1500 line vimrc and plenty of plugins (including my own), so you don't get to assume I don't grok the vim way of thinking :) I've heard the "macros is the same" sentiment many times, and usually it's from people who have never had much experien…
This may only show that you grok VimScript way of thinking, not Vim way of thinking.
You need not re-record a macro, a macro is stored in a register. Just edit the register, and you're good to go with you new, (supposedly) improved macro.
In Vim, you edit in Normal mode, and insert in insert mode. Multiple cursors is a means of moving editing into insert mode, and thus in spite of the Vim way. I am an Emacs user * and there is a multiple-cursors mode for Emacs, which quite useful as Emacs is modeless.
* If we're doing SLOC porn here, I've a ~400 SLOC vimrc with nice gems in it, and is nicely and extensively commented. I've switched to Emacs for my love of Lisp and newfangled dislike of some parts of Unix.