Personally, I think that revoicing an arranger's ROM tones is merely an acknowledgment that they simply didn't get it right the first time.
All I'm hearing about OS 1.4 (whoops! meant to say OS 4.0

) is that it adds a few more audio chords (but zero details - didn't even get ANY details about OS3 either) but STILL doesn't allow the audio part to exist without MIDI guitar substitutions, so it STILL doesn't live up to its' initial published specs... It revoiced some of the tones, adds a few more styles and FINALLY you get some sort of rudimentary style editing.
And you are comparing this to Korg's complete redesign of the synth engine, Guitar Mode and adding the equivalent of SA capabilities?

'Lowered Expectations' seems the mantra for Ketron.
It's all well and good to claim that ANYTHING added to an arranger should have been something added right from the start, but Korg and Roland added very powerful features to an arranger that ALREADY worked well. They weren't bugfix upgrades (even though some were squashed at the same time) but were the equivalent of what Yamaha do, without the onerous task of selling your current arranger and buying a new one

You want new features on a Yamaha, you HAVE to buy another Yamaha. You want them on a Korg or Roland, you wait and see what they are going to give you for free. You want new features on a Ketron, you have to wait until the features it is SUPPOSED to ship with get added first...

No doubt Ian will chime in here with how successful Yamaha are in this market. Which only proves that stiffing your customers IS the way to make lots of money. Greed is good!

Yamaha could have easily added SA2 to the T2 or the new Guitar NTT's in an upgrade. Hands up everyone that ENJOYED selling their T2 and paying a LOT more for the T3, knowing that Yamaha COULD have added SA2 and the new NTT's for free?

I'm pretty sure I WON'T be moving to Yamaha in the distant future simply for this one thing. If Roland had followed Yamaha's 'rape your customers' policy, I doubt I would be staying with them, either. But my G70 does a LOT more than when I bought it, and most of the things that got added weren't things it needed to work right OOTB, but entirely new capabilities. Roland saved me a fortune. Kudos to THEM...