GPU management is not absolete because haiku is not going to stay in "non hardware accelerated" state forever so I'm not going to rely on a program which doesn't support that by default.
Speaking of image processing algorithms it's a very very huge field and will take an entire lecture to give the bigger picture on this matter.
In short i'm not talking about subpixel and LCD support here.
There are a bunch of other mathematical algorithms which evolve with each and every new version of Photoshop for example. Algorithms for: Scaling, Resizing, Optimising, Reading, Buffering, Noise removal, Content recognition and/or removal, 2D compositing real-time(especially this one, in photoshop it's called smart filters), Color correction, RAW image support with all modern packing algorithms that camera manufacturers provide on regular basis. I can go on with this infinitely going to hardware specs like CPU architecture based optimisations etc etc.
To answer your question, Recfraction can't even resize an image as good as for example Photoshop or Gipmshop or Pixelmator or you name it modern editor does, and it's not only about the algorithm it uses... Photoshop's Bicubic alghorithm for example differs from Corel Painters one though both are based on the same essential algorithm developed 35 years ago. and when it goes to professional tools you can't just say "I have subpixel rendering" or "I can resize those photos too".
