Just to echo many of the suggestions already made..
• High resolution, user-customisable or importable editable oscillator waveforms, editable via Virus Control and uploaded/saved to Virus TI.
• More advanced sound manipulation at the fundamental oscillator level (before it gets summed with other oscillators and they then hit the filter, effects etc.), similar to Z3ta+ (Warp, Twist, Drive, BitReduction, etc.)
v
Essentially these bits:- http://www.infekted.org/timo/z3ta.png
• OLED or touchscreen display with oscilloscope, like Korg Minilogue http://www.infekted.org/virus/…various/korgminilogue.gif ... or Bluetooth connection to iPad for larger graphical user control
• Ribbon controller or XY pad for tactile hardware expression. Synthesis is all about performance modulation and unique performance possibilities can be achieved with a ribbon/XP-pad that are unattainable from any other method, such as tapping, gating, scratching, vector-based swipes, controlling two mod sources (axes) at the same time, having greater tactile dynamic control over creating smooth curves, etc.. all with just one finger. Again if the Virus can be sync'd over bluetooth to iPad/iPhone you could perhaps use those touchscreens for this functionality instead, depending on latency/lag.
• Additional Arpeggiator functionality, more specifically:-
- A new 'Accent' control (where you can further overlay velocity pattern[s] over and above the arpeggiated note pattern), and control the blend of the accent.
- More 'Motifs' (an increased selection of different orders of notes played, not just the usual up/down/up&down/random/chord/as-played).
- And... Additional customisable note patterns themselves.
(The above are used in the older Roland MC505's arpeggiator functionality to great effect: http://www.infekted.org/timo/mc505-arpeggiator.png )
Live example of an Accent (velocity) pattern slowly being applied and then taken away on top of an arpeggiator note pattern on MC505: http://www.infekted.org/timo/mc505-arp-accent.mp3
• Increased modelled filter types (MS-20, TB, JP8, OB-X, Arp26, etc.)
• Two patches at the same time, with a crossfade or morph feature to mix or blend from one to another. I know this is essentially a two-part multi, but it would be nice to have it on the front panel quickly and easily within reach.
• Faster LFOs, as the current ones tend to alias at higher frequencies
• Scalable Virus Control PC user interface, to keep up with higher resolution screens.
• Standalone VSTi mode for noodling (rather than having to use something like Savihost. etc.)
• A Compressor/limiter, along with being able to chain effects in any order.
• 49-note Polar
• A partridge in a Virus TI Three. 
Come on, Access, give the guitar guys a well-earned rest and show some love to your original synth user base! 
Merry Christmas to you all and best wishes for 2022.