I migrated my site from its old domain over a month ago. I followed Google Webmaster Tools completely, including 301 redirects from every existing URL to the new domain, and then submitting a change of address. Traffic continued as normal, but then a few days after submitting the change of address traffic plummeted to about 20-30% of what it was previously.

Most of my traffic comes from organic search, and I can see that for the keywords I had targeted before and performed well with and am now ranking much much lower for. In some cases for low competition keywords I've only lost a few places, for higher competition terms I have really suffered. This has started to pick up a bit (one of my keywords I have risen from 195 to 100 in the last week), but it seems to be a very slow process.

How seamless is this process normally? I was under the impression that this would not affect my rankings too severely, but it has now been a month since the move and recovery seems to be very slow, if at all.

Is it likely that I've missed something? The only change is that I have moved what was the home page to be more of a sub-page, and now in its place is a magazine-style home page. I understand that links to the old site will now be pointing to the latter which means that rankings for some keywords attributed to the old home page will take a hit, but even on other pages that seem to fit in exactly the same page structure as the previous site I have seen a drop in rankings.