When you say Wordpress, you should clarify: do you mean Wordpress the CMS, or Wordpress.com, the host?
Wordpress the CMS
Wordpress as a CMS is a freely available tool that can be used to quickly and easily make websites and blogs. If you're going to host a Wordpress site on the clearnet, you will have to sign up for a hosting account. This gives you the flexibility to choose a hosting provider with a good track record in security, but still makes you vulnerable to government intervention.
Another route to heavily consider is hosting your own Wordpress blog on the deep web. This limits your readership, but heightens your security greatly. You can use practically any computer made within the last decade to perform this task, and with a good tutorial you should be up and running within a day at the most, if not hours.
Wordpress.com the Host
If you were referring to Wordpress.com, then you were talking about a company that offers hosting of Wordpress blogs. From what I've heard from people using Tor Browser with Wordpress.com, the results are far from optimal. Speeds are slow, and the only security you gain is that Wordpress.com doesn't know where you are.
If you're worried about your Wordpress.com account being compromised over Tor, then yes, it's a possibility. There's something called exit node listening that lets someone at the end of your connection capture your username and password, as well as any other data transferred. Theoretically, if the runner of said exit node a) knew who you were, b) knew what to capture, and c) was a member of whatever evil organization opposes you, your account could be compromised. You also run many of the same risks you would on the clearnet; your account could be taken down by petition to Wordpress, or your account could just be hacked.
If you want security, go with Wordpress as a CMS. You can download it from Wordpress.org. The risk of doxing is minimal, unless you post information that could lead someone to any real-life accounts or information.
If you want readership without using a Tor proxy (which is totally an option) AND you're dead set on Wordpress.com, the best I can say is to watch your back. It's far from the best option, but if you're careful you can probably be relatively safe.