I may be weird, but one of the things that (to me) is an advantage of Sequential instruments is actually something most probably do not even care much about... it's MIDI specifications. It's one of the things that is always well spec'ed on Sequential synths, and organized in a way that even an old program like SoundDiver can have editors made for the synthesizers... it's actually a part of a synth that I study REALLY carefully before I buy a synthesizer... the only exception to this is the TEMPEST which really sucks in it's MIDI specs.
Of course the other aspects of a synth is just as important, but I believe that because Sequential is not packing their synths with extreme loads of features that would complicate the MIDI specification (like TEMPEST again), their synths appeal to me. They know how to make their synths focused, but still flexible enough and with a deep engine.
I'm almost 100% certain, that synths like MOOG ONE and QUANTUM, though very powerful synths, are so complex that it's MIDI specs for SysEx would either not exist, or be so convoluted you would have program a dedicated editor for them in some way... using a universal editor-maker would probably not be feasible because of the complexity, and as long as Sequential do not create their own editors, this is crucial to me. So I hope Sequential will continue this trend for years to come.
When it comes to new synths, I'm not really sure about what I really want to see anymore... aside from the obvious better MIDI spec'ed TEMPEST that I'd certainly like to see, I guess that there are currently enough options if you just want some deep polysynths, analog or hybrid... a new synth will almost always give you something others do not have, but many will (if their engine is deep enough) overlap so much you could do most with all of them... you really do not need 20 different axes to chop a tree if you need to be honest about it would you?
When the big polysynths with deep engines have to compete, I feel they all do the basics so well, that this is not really a selling point anymore, something else is needed, and to me what is needed is CHARACTER (in the audio itself), to make them more interesting, because let's face it; you REALLY do not need more synths do you? ... you can make music FINE without another synth, and I think that's what makes it hard to come up with yet new and innovative stuff really because they need to convince us, that we NEED a new synth, even though we really do not.
But we are not just creators of music and sounds... we're also collectors of synths, and that's what drives us to get more... and more... and more... but at the same time, we want to justify the purchases, so we keep on wanting new features, new character, more flexible engines etc. etc... Maybe it's just time to think about what we NEED, instead of what we WANT?
I'm not talking about stopping being innovative, and create synthesizers, but maybe everything is just happening too fast, and more time should be spend perfecting what we already have instead... many are buying new synths even before they have utilized their latest purchase to their max... like a row of "half eaten pies" in a line behind you... typical neo-liberal consumerism at it's ugliest.
Anyway... we will never be making any music, if we constantly focus on all the innovative stuff that has not been made, and that we do not have... but I guess that's a human trait... always longing for what we do not have, instead of using what we DO have.
End of rant...