One thing I've always felt about this SCP series, even on the old wiki, is that it doesn't really look all that top secret and official, and I know some people agree with me. I doubt an organization which is looking after objects capable of destroying the world uses a wiki to store information about them. Now, I do understand why a wiki is used, and the fact anyone can edit is good, but I really do think it lacks that edge which changes it from a bit creepy into scary.
I think one big change which would help the site would be instead of a happy looking wiki news front page, there is a serious, believable one. It could be a plain looking login screen, or maybe even the website for a cover of the institute (? Not sure on name.) which they use to disguise their efforts, and when you click on a link it looks as if it glitches out and lets you access this SCP's and so on. You get the idea.
Now I'm not sure if this is possible, but I do think its worth trying.
Another way to make this all feel more real would be to have a second website. The front page could be one similar to those I suggested above. For example, if it was made to look like a front for the institute, it could have a few 'Our Vision' and 'Goals' pages, and just be like a bog standard large company website. Then, when a certain link is clicked it could 'glitch out' and then load some kind of database page for some SCP's (which would just be copy and pasted off here). I know its a rough idea, but I really think it has potential. It would be a more believable site for this, it would be sort of like a hall of fame for the best SCP's, and if we put a few links to this wiki it should hopefully increase the number of editors.
Sorry if thats all a bit rambly, but I'd like some feedback on it.