Simblr!

It's fine. I'd probably just add some hashtags for some posts so that when they're searching through your archives, it'll be much more easier to find alongside with your navigation section, such as: #sims3 #ts3 #asks #cc #lots #nocc #screenshots #exchange #wcif #lookbooks, and others within the category like: #clothing, #genetics, #shoes, #legacies, #reshade, #downloads, #conversions (whatever game it's converting into), etc. 

Hyperlinks to said content (if easily accessible). No dead or tedious links. If dead, then the asks section would suffice for this.

Maybe look into opening a search bar? Another easier way to find what you're looking for for when your blogs get too long and the viewer may not want to sit through your whole catalog of archives, so they'll just type in a word of sorts in hopes that they'll find the post(s) that they're looking for.

A resource tab as to where you found your most favorited sim content (that may or may not exist) as well as your tumblr theme and other blog aspects.

If this is your main blog and you wish to use it for all related sims 3 content, then go at it with what you want to post, but if you want this specific blog to be about just uploading downloadables, then label it as such, or if you all wanna do is post screenshots and storylines of said challenge(s) and household gameplay, then do that. Sometimes it gets overwhelming at times and you just want a break from one side of your platform and focus on other, more fun things that'll give you less stress.

If you are going to be making your own builds or uploading sims to your blog, I'd make a note stating on what packs and/or mods you're using so that others can determine as to whether it's worth downloading. I'd also add links to said cc of .sim file, though I think it's just simpler to just upload the sim with it's content inside the folder since some simmers tend to think that that file itself exports said cc, but it doesn't. With the launcher, you could from the game export it and then later on download it from the exchange or wherever you got it from, and then the launcher would install just about all the cc and it'd appear in CAS, but I'm not sure how that is like now with the EA App (does ts3 launcher even exist?), so that's why I'd say upload them in .package/s3pack file form, though .package would be less taxing in the end. Also, if you're doing builds for a project or whatever, then I'd mark the post as a WIP, it's lot size, and whether or not it's (un)furnished.

Other than what I can really think of, you got a decent format for a sim blog.