I feel a Singed VGU is gonna be extremely difficult

The reason for that is because of his most iconic and also problematic spell, his Poison Trail. It creates a unique play style yes but that play style basically calls for you to not interact with anyone else in the game.

Almost every Singed will run behind your turrets and proxy and if you try and deal with him he will run away at mach 5 speed wasting your time and then just come back and do it again. Yet if you ignore him you will never be able to push your lane because you won't have minions. At some point he will sit in your base proxying 2 waves at once which can cripple entire teams because it forces multiple people to deal with him causing you to lose pressure on any objective. Even if you do send people to deal with him he will pop ghost ult and run the heck away yet again wasting time of everyone involved.

Perhaps whenever it is time for Singed to get his VGU Riot will know of a way to keep the poison trail while making him more interactive with people in the game and not just a proxy bot.