The improvements that Castle state are not specific and you could say that every single OS release has met these criteria from Arthur onwards ! I strongly suspect that Castle realise that they be losing the initiative of OS improvements and are trying to deflect attention from the advances in Select. The bottom line is that the Riscos market is small and duplication of effort is utter madness. I'll say it again can somebody physically close to Jack and Paul knock their stubborn heads together. The excuse that features in Select can't be ported to RO5 that's bull.... It's a smokescreen for "Jack and Paul can't agree a way forward but don't want to admit it".
Reality check to all those singing the praises of Castle as the "only" way forward. If you want more applications then you MUST have a single OS otherwise developers will have horrendous problems getting code to work with both versions. These problems will increase as the differences increase. I did a quick search for some rough numbers and from what I can glean if an application developer concentrated on RO5 only, they would lose 80% of the userbase !!!!!!!!! frigging hell come on people. The survey on Iconbar states that 20% of users are RO5, 71% are RO3.7,4,select, the remainder are pre 3.7. So the economics of the current riscos marketplace would dictate that an application would make more money ignoring RO5 not embracing it to the exclusion of all others.
Now I totally agree that the future is ARM hardware not emulation but there is still more none xscale ARM hardware in use. It would be a no brainer to provide an upgrade path through RO3.7,4,select to RO? where RO? is the branch re-joining. People would use applications and an OS with super duper features which go slowly on a Strongarm but fly on an Xscale. They would then be desperate to upgrade to the latest hardware are you listening Jack ?. Otherwise people are amazing at living in ignorance with old applications. You bribe people with software features to purchase better hardware ! (Microsoft do it all the time with unbelievable success). You also solve the problem with people having invested in Select (more users than RO5 don't forget) who don't want to see their investment as a waste of money.