Thanks for sharing your thoughts! Yes, the recording I put up in spring was my first performance of it, and I haven't performed it in its entirety since then, but I've done selected movements in lessons and masterclasses (recently posted 1+2 from a masterclass earlier this summer). I'm copy-pasting a few of my own thoughts from another forum:
I've done a lot of effort in order to gain clarity here, which isn't an easy thing. Keeping notes a tiny bit more detached (or at times rather light and leggiero - if we're talking 16th note passages low in the bass for example, where it'd just be a blur otherwise) is one way to do it, but even more importantly, I'm trying to project the music that's going on beyond the constant 16th note figurations, which are present throughout the piece. Beethoven adds "con alcuna licenza", so, it's a fugue with certain liberties. Liberties usually mentioned are doubling of bass notes and that there'll occasionally be more than three voices, but just as important to mention in my opinion is, that there's a very clear hierarchy between the voices sometimes where a 16th-note figuration might simply provide a harmonic framework rather than sounding like an interesting voice in itself. In places where this happens, I find it useful to highlight other voices that usually move with slower note-values - and I think it helps avoiding monotony. But yes, greater contrasts and dynamics could be done. It's a problematical piece in this sense because there's no way to make it "sound pleasant", and it's not meant to be that way. Still, you don't want it to sound as though Beethoven wrote sempre fortissimmo for the whole fugue. I had very interesting lessons on Hammerklavier this summer and did get the advice to find places to make color changes and pianos, however, I got rather limited advice on where this should be done...