A way to for GW to move in a different direction with IG perhaps.
The way that GW's 'different directions' have gone in recent times, this worries me!
I'm not sure how they'd manage to re-vamp IG but still maintain a sort of generic look that can suit many different types of army. The Cadians are great for that because they're so versatile, they just need an updated set!
I terms of Killteam I don't play but I would reckon if they made an IG team it'd have to go down the route of being a bit more of a focussed squad structure, having a few specialists and strong use of tactics rather than the 'meat for the grinder' approach! Maybe an IG SAS of sorts. Either that or they'd choose the Tempestus Scions *ahem Stormtroopers ahem* route?
One thing I have noted with the TS Hot Shot Volley gun and the Primaris SM auto-boltgun option is that there seems to be a move towards automatic weapons that I assume are good at pinning your enemy under suppressive fire. I wonder if the future holds an IG man-portable weapon for suppressive fire that isn't just a grenade launcher or a HW team... hmm...