There are a few classic amps that are missing from the Helix -- I'd like to see a blackface Princeton Reverb, a Tweed High Power Twin, Marshall Jubilee, Bogner Ecstacy, and EVH 5150 III.
I'd also like to see some new stomp boxes: Boss Dimension C, JHS Angry Charlie, Suhr Riot.
Being able to store Power Cab settings in a preset would be super cool, so for example if I switch from a Mesa Lonestar model to a Plexi then the Powercab would change from a V30 to a Greenie.