1. WordPress/ComicPress: Sorry, Sir, but your services are no longer needed. I've built my own site on ComicPress.*
2. Precarious financials: Drunk Duck is a public company, and reports of their fiscal health are pretty dreadful. Not to mention blaming it on the incompetence of departed employees. No data about other hosts. I hope they're doing better.
3. SEO: You can't thoroughly optimize your site for search engines if you are just a subdomain of another site. Your presence helps the host look bigger, but you shrink.
4. New era stats: They're not widespread, but the new tools for adding details to whatever analytics you use don't always deal well with subdomains.
5. Status: Your own URL beats anything you can get from a host.
6. Erosion: With most hosts losing traffic, the communities get smaller and so do the audiences. Then more people leave...
7. Mirror sites: When comics that started on your host leave their original site up as a mirror site to attract additional notice, it adds a ghost ship to your community. When people Googling that site see that the best search result is the one that does not have your host site in the URL, it forms an impression.
8. "New" ComicSpace: Could still happen, but the climate for hosts has shifted dramatically since it was conceived. I'm underwhelmed by everything else this team has done, and puzzle over how they could have hired well. Answer: I think they did not, especially when it comes to design.
9. Even high school students with messy comics are managing to launch their own site. There's more people around than ever who can help you get set up if you are having trouble.
10. Potential competitors who could have posed a challenge to WordPress have gone through various forms of self-destruction, from Movable Type to SynthaSite (now called Yola**, of all things). With so many people now using the same tool, it's easy to look at the myriad of choices from one year ago and see how obvious the choice is now by comparison.
*For the record, I finally learned enough about programming to take a pass on WordPress, but I like that it's allowed many people to break through the knowledge embargo and post webcomics. Besides the fact that it's making comics look alike, you can't get cutting-edge creative with it unless you add custom programming, and if you're going to do that, you might as well build a site or have one built to your specs. Also, because a custom site coming from WP will require a rebuild, it's going to stop a lot of people who have built elaborate WP sites from making the jump. It's a great choice for many people, but as much as it's making participation more democratic, it's also a steamroller of blandness.
**Promising but evolving and occasionally troubled product; weird company. Good for small quickie sites or learning in a visual way how a lot of web architecture works. Not suitable for a webcomic, though I've managed to make mine work with great exertion. Am moving all my sites to my own architecture in the coming months. Lately their site update server has been offline a lot, and we missed two update deadlines in one week.