It would appear that you've woefully misinterpreted Michael's email.
Moving common functionality (such as full save, page searching, textareas, treeviews, scrollbar widgets, etc) into the cross-platform core is the correct thing to do to reduce the effort required to produce a platform frontend.
As part of this process, APIs get redesigned to be significantly more sane. A great deal of the RISC OS-specific code makes assumptions which do not hold in the core of NetSurf (which has to be portable).
The result of these API changes, along with other, less obvious, differences is that the existing platform frontends then require fixing to work with the new core functionality. Unfortunately, there's been nobody to do this for the RISC OS frontend for the last 2.5 years. During that time, any such fixes have generally been made by Michael or myself.
I have reached the point where I can no longer commit significant amounts of time to fixing the RISC OS frontend -- what time I do spend on NetSurf (and, for the avoidance of doubt, I've written the best part of 50,000 lines of code in the last year or so) gets spent on improving the core engine.
Therefore, we have a choice:
1) Continue to perpetuate the myth that the RISC OS frontend is actively supported.
2) Ask for someone to come along and maintain the RISC OS frontend.
3) Remove the RISC OS frontend from NetSurf as it's getting in the way of necessary changes for the long-term good of the browser.
As I've explained, option 1 is no longer viable. This leaves options 2 and 3, which Michael's email outlines.
Our preference is clearly 2 -- dropping support for any platform is not a decision we take lightly. However, when it gets to the point where progress is being hindered, difficult decisions have to be made.