some ideas:
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sidechain for dynamics in inputs AND busses, with flexible routing from all inputs and all busses
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a ducking-function in busses, with sidechain and with adjustable max. depression.
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possibility to insert channels, when a new channel must inserted in an existing channel-list (inclusive preamp-gain!).
not long ago, I must insert an additional tom-channel - and move all 30 channels behind them, per copy and paste preamp, channel processing and mixes = 90 actions = what a stupid job, and not one mistake is allowed!
ok, in livesituations I can simply insert a channel from anywhere to the new position on the surface. that´s easy. but for coming events, I need a correct channel-list, I´m a german 
the lowest an the highest band can used as locut/highcut/bell/shelving-filter. this EQ is for outputs - and for inputs(!) and give us a maximum of flexibility.
why? all desks in this world have a 4-band input-EQ, whitch is in 99% functionally adequate. but, is this really necessary forever? sometimes, I need an additional filter for example for feedack-reducing in critical live-situations, or a locut, 4 band-EQ and a highcut in a channel.
maybe, the hardware-EQ buttons can have the normally 4-band EQ for better overview, and the additional filters can be used per touchscreen.
I think this can be an innovation in mixerdesign - and an unique selling point!
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automatic-mixer function to integrate the iLive in fixed installations, or for better handle double microfone-installations at lectern-situations (witch is mostly uneffective, but sometimes the customer needs it for different reasons)
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two screens for jobs with two technicans in the same time or for better overview.
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screen with overview of all dynamic-LEVELS (gates, compressor, limiter/deesser)
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don´t forget: the screen must have a good visibility also in open-air requirements.
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like “vilddyr”: a better control for the limiter and deesser.
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like “vilddyr”: a better quality for the surface, please!
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dynamic-EQ as alternative compressor-function in input-channels.
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Dante network inclusive gaincontrol. i think this is really the future.
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gaincompensation for FOH + MON systems.
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a much faster boot-time
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much faster scene-safe and -recall (for complete scenes)
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more FX-blocks, and with a distortion-FX! - sometimes the iLive sounds too clean 
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samplerate:
48kHz is IMHO good enough for live-situations. I have no problems with it. the latency-time in the existing iLive is very good!
but: why not, with 96kHz we get a latencytime like analogue desks? 
maybe you can make a switch between 48k and 96k?
oh, this is a long list… sorry.
and now: I hope you can understand my english 