On the Way
Advanced Find Bar (coming for 3.0)
The find bar should be able to search for more than just exact phrases. Take part in the in-depth discussion.
Foreign Languages (coming for 3.0 or 3.1)
I see from addons.mozilla.org's stats that Deviant Love has quite a few non-English users! I'm sure some of you would appreciate being able to use Deviant Love in a language you're more comfortable with. However, this will have to wait until I add an options page, which will come in 3.0, as I'd like for you to have the choice between your language and deviantART's language.
Skins (coming for 3.0)
This is a community of fantastic artists, and I can't wait to see what you'll do when I give you the power to give Deviant Love a makeover!
Thorough Scanning (coming for 3.0 or 3.1)
Deviant Love currently scans by checking your Faves page's Web feed. This makes it immune to any changes deviantART makes to its page layout and provides a few other bonuses, but unfortunately the web feed doesn't include Gallery folders, Collections, or members-only deviations. I'd like to add a mode that will detect when something is missing from the Web feed and fall back on HTML-scraping when that happens.
Subaccounts (coming for 3.0)
When artists set up multiple accounts, Deviant Love will empower you to view all their works under one name.
True Artists and Collaborators (coming for 3.0 or 3.1)
Some deviations are collaborations between multiple artists, or are simply commissions or whatever that the artist permitted to be submitted by someone other than themselves. This feature will let you see a deviation under all the relevant artists' names.
Keyboard Navigation (unscheduled)
I'm not sure what the demand is for being able to use Deviant Love entirely via keyboard, but it'll make great practice for developing accessible web applications for me.
Firefox Addition: Restartless Install/Update (coming for 3.0)
It would be awesome if newbies could try out Deviant Love hassle-free and oldbies could get Deviant Love updates instantly. Of course, since restartless add-ons are a new feature of Firefox 4, Firefox 3.6 users won't reap this benefit.
Stored Deviation Recovery (unscheduled)
Artists understandably want old and embarrassing works to get less publicity, but when they achieve this by storing deviations, those of us who truly loved it lose out. Stored deviations remain on deviantART's servers, and Deviant Love could record the locations of all your Faved deviations when it performs its scan so that you can still access them if/when they get stored.
What's this? A mysterious future feature that Pikadude won't talk about? What could it be?? Well, one thing's for sure; if it was anything that actually affected how you use Deviant Love at all, he's just tell you about it, instead of writing a weird note about it in the third person. This feature will have roughly the same effect on your Deviant Love use as version 1.0.3's new feature of having codenames for each version.
Open For Discussion
This would be pretty easy to add since I've already got Firefox support, but you need to let me know it's worth my time! Let me hear you, SeaMonkey people!
Web App for Unsupported Browsers
Internet Explorer, Safari, and Opera and mobile browsers are basically never going to have a Deviant Love extension written for them, but I could make a Web app that gives you the essential Deviant Love features, and even make a bookmarklet to make using it easy. More details...
Support for viewing thumbnails of your Faves could be added, though it may take some redesigning of the interface. For a lot of little reasons that I don't want to discuss, I don't want to allow viewing more than one thumbnail at a time.
Currently, the heart doesn't appear until your browser says the HTML is done loading, and Deviant Love grabs all the information from the HTML it needs to perform the scan. What if the heart could appear the moment your browser starts displaying your Faves page, and if you click it before the HTML has loaded and Deviant Love has its information, it'll start the scan just as soon as it does?
Group Gallery Scanning
Deviant Love can already scan Group favourites; is there interest in having it scan galleries as well? (Note that if I implement both this and Instant Heart, Instant Heart won't work on Group galleries.)