The only real changes would be ability to max out Wyche squads and then add ICs, an additional Grot in a Grot Raider, and an option for a tad bit more dakka if you like Gunboats.
Since Wyches currently are terrible as assault options, Grots don't really need the boost, and the dakka thing is pretty minor...eh. Probably the Grot bomb would get the most boost, and it wouldn't be that big of a shift. I'd probably keep just running 4 of them, myself, but will admit sometimes that feels a bit squishy and I might go to 5 if points allowed.
Wouldn't be a change to most things, really. I rarely max out my Raider capacity as is, and the only people I know who do tend to do it as Gunboats and though they probably would be happy at the extra 2-4 shots I don't think it would really be a game changer.