Torn here. The province needs better transportation, full stop. The bike lanes will get reinstituted at some point in the future after Dougie loses an election. Bike lanes are a partial solution to inner city gridlock, not a cause of it, again full fucking stop so I'm not worried about that part of it in the long term despite how ridiculous a move it looks like now.
In a vacuum I'm not opposed to highway 413 either. The 401 is hilariously bad and creating a proper highway network by using the 413 to connect with the 400, 427, 410 and 403 into a single continuous network looks smart and efficient. These are routes that there are no existing or proposed transit solutions for. The metrolinx 2041 plan will in theory create efficient movement into and out of the centre of the city to bedroom communities, but there's nothing planned that would replace the 413's ability to let you skip the middle of the city entirely. The only other option is the 407. Which this probably paves the way for buying it back (for too much money and for it to go down as one of the worst moves in Canadian infrastructure history when viewed from first shovel to end of life) and having a pretty pretty good highway network in a region that has grown massively over the last 20 years. Mississauga and Brampton were suburb communities not that long ago and now it's a urban block unto itself of 1.4 million people. If it were considered a continuous municipality it would be 3rd largest in the country by population and not too far off of Montreal for 2nd. It needs better transit of all types.
Quick sidebar, but the bradford extension is an okay idea for similar reasons. It would allow a fairly signficant amount of traffic to skip going through the middle of the city to get east of Toronto. It still forces a 407 trip if you don't want to fight your way through Scarborough but it takes a good chunk of time and cost off of anyone coming from north of Bradford who currently have to get on the 407 at Vaughan or run the 401 gauntlet.
With all of that said. I don't trust that this won't turn into a super sprawl land giveaway to Dougie's construction donors, turning the new highway into a brand new traffic nightmare within 10 years because enduced demand is a fucking thing, stop trying to pretend it isn't. If this was a highway simply cutting through the greenbelt I wouldn't be overly worried about the environmental impacts (and them not making the reports public....). A similar highway run through York & Simcoe County farm and forest land without much environmental issue (including the holland marsh). But a highway accompanied by endless subdivision sprawl at every interchange would be the exact shit kicking of the greenbelt that environmentalists have been warning about for decades and the reason it was protected in the first place. I see the possibility of this being part of a really nice blended transit strategy with the metrolinx improvements and Toronto's economic growth stops being forced to drag a broken transit system around with it, but I also see the possibility of Brampton turning into twice the bloated sprawling mess it is now, Bolton-Nobleton becoming one big fucking amorphous blob of a 200-300K person subdivision, Georgetown basically becoming the same, etc.