Thanks Piru.Probably only hyperion could really know.
However i think that features like :
Hardware compositing engine (Radeon R1xx and R2xx family)
Implementation of the "Cairo" device-independent 2D rendering library could be a little difficult for a processor of only 200/233 mhz.
And since the required hardware for amiga os 4.1 is AmigaOne (SE/XE/µa1-C), Pegasos II or SAM440ep / SAM440ep-flex then things could be a little difficult for the classic phase 5 users.
(with only 256 mbytes of ram,if timberwolf is ported how much memory would be left if someone opened 5-6 tabs of heavy pages ?)
Os 4.1 need a radeon 9250 to run well,that would mean that most classic users could only work with a3000/4000 with mediator solution.1200 mediator solution would not run well.
Off topic but to me it seems that since the appearance of sam and os 4.1 ,os 4.0 seems like it has been left behind by hyperion.