Per a chat with @jack:

<ashley> it's just a very intensive process; but given that we already requires JS in order to use the special page, maybe we can leverage some of JS' power to overcome that
<ashley> basically each request has certain limits within regards to how much time it can take and how much memory it can consume
<ashley> these limits are defined in GlobalSettings.php
<ashley> but individual things can -- and in the case of CW, will -- override them to higher limits
< ashley> but even these higher limits aren't enough for something like CW
<ashley> and even though the server should have plenty of RAM etc. we can't just keep continuing throwing memory and time at it --> rewriting is the only viable solution
<ashley> if you look at /extensions/CreateWiki/CreateWiki_body.php you'll notice (L88-89 & related comments above) that we allocate 256 megabytes (or 1/4 of a gigabyte in other words) and 120 seconds to the CW process but despite that those are like twice what we allocate to normal page views (in GlobalSettings) it's just not enough
<ashley> the problem is basically that on the final (4th) step of the creation process, the user presses "create my wiki" which starts the whole creation process -- we probably need to use JS to execute individual parts of the process and only, say, create the necessary directories after the previous step (database initialization or w/e) is complete