Can I just spit the raw HTML at you? Do I need to inline images? I'm assuming that someone who's consuming a full feed isn't going to want any CSS included.
I'm not against this, but I'm also hand-coding all of my blogs, and this seems like a problem that would be more easily and more consistently solved by a user-run service like the one you've made. I don't know what readers currently support, and I'm looking around quickly on DuckDuckGo and not seeing many resources about generating full-text feeds that don't boil down to, "click the button in Wordpress."
Again, I have no problem supporting this, but if I'm going to put the time in to change my blogs, I kind of need more prodding than just one or two people saying it annoys them. I don't have any specific reason I wouldn't want to accommodate people like you -- I'm not advertising on my blogs and I don't have any analytics, so I don't care where you read. But I don't want to invest a lot of time into building a completely new content pipeline.