I'm halfway tempted given I've replaced almost all of my stack with my own code barring the browser and X. I think, if I was going to consider and "X12" though

I'm halfway tempted given I've replaced almost all of my stack with my own code barring the browser and X. I think, if I was going to consider and "X12" though, what I think would be the steps to start with would to trim the starting point down aggressively, to reduce the maintenance burden: * "Promote" certain extensions, like BigRequests and XRender and enable them automatically. * XRender requires a fixed set of visuals, including 24 bit and 32 bit. As a result, if you require XRender you can reasonably aggressively deprecate most inferior visuals. You might lose some old software without shims/a proxy that way. But frankly I don't think it's worth caring enough - if any of it is worth keeping, a shim is fine. * Aggressively deprecate most legacy rendering calls and options. Almost all of it can trivially be shimmed client side or supported via a proxy if any extant/in use apps still support them. This includes support for server-side bitmap fonts (they can trivially be supported by XRender glyph support). * Remove most backends. Support maybe one "dumb"/basic backend for legacy use, but remove as much possible. The point is you can do a vastly better job if you strip the thing bare first.