I too was into the romplers from the yamaha's,rolands etc.. but I hated the lack of efx, or the limitations, even had the kronos for a while, but similar issues we're still around in the modern boards, a keyboards voice mode, isn't the same as their sequencer mode..U lose the ability to retain MFX,all the great cwork done to a patch in voice mode, lost in sequencer mode, Korg being the better outta of all of them, the kronos, was alot better then older Korgs for this, but still not great imo.. to me that sucks,recently over the years I've been able to find some really good sounds by layering the favorite sounds/ synths I've gathered inside Kontakt and other vsts , much better then what I've ever had in keyboard romplers.
Sampletanks def got a sound, might take a few patches to get that big sound, but there aren't those limitations you find in romplers, n sampletanks old.. S3, is supposed to be shown at Winter Namm 2014, u might wanna check it out.
M5v3 is a beast,if your into building your own sounds, scratch that, anything from UVI is leagues ahead of most,so def give them a shot, but they have a heavy price tag.
Honestly, I think if Yamaha and Roland, we're ever to go software, they would be huge to musicians,but I think they are too stubborn, n feel they must carry on a hardware tradition. Imagine a modern day Motif or Fantom software rompler, not a rip off halion sonic, but a true emulation of their stuff, that would be slick, but I doubt they would ever do it.. till then , create your own sounds, tweak them till they do it for you, cuz honestly, thats all they are doing in their keyboards.
cheers
Interface : SSL Bus +/SSL Fusion/Silver Bullet MK1/Presonus 32S/Orion Studio
Textures : Mpc X/Kurzweil K2700/Korg Prologue 16/Sequential Take 5/Deepmind 12D
Pedals : Strymon Big Sky+Timeline.Eventide H90