I'll break it down how I see it.
His first year was interesting and I have problems with it, but I respect it because he set a plan, followed the plan and improved the team across many key areas.
Cam Talbot: The most important thing he did as the Oilers GM. I'm not going to laud him too much for this trade because Talbot wasn't his first choice. They were in on Lehner until Bryan Murray (RIP) priced him out of the Oilers range. That would have been a disaster. Still, props for him for not only getting the goalie but giving next to nothing for him when Sather originally wanted a 1st.
Andrej Sekera: Huge signing in his first year. I was very concerned that he would fail to upgrade the D after a spring filled with talking-down the notion that he would be whale hunting in the UFA pool. Sekera is the teams most consistent, well rounded defenseman and we miss him a lot.
Griffin Reinhart: I was initially optimistic because I didn't love the draft pool. I felt Reinhart was still a good, if not great, prospect. It was entirely too much to give up, though and obviously is ugly as sin in hindsight. Doesn't help the optics of it now that Matt Barzal just had a five point game and Reinhart is now officially past suspect territory.
Zach Kassian: It's an astute risk to take and I'll give him credit for that. The thing here is, it was obvious Kassian was a decent player who brought speed, energy and physicality to the game. What Chiarelli couldn't know when he made the deal was whether or not Kassian would stay sober. Every team in the league knew what they could get from Kass; Chiarelli is just the man who rolled the dice.
Patrick Maroon: This one worked out like crazy, but again, let's not pretend that Chiarelli saw 27-goal top line complient to McDavid in the scouting reports. It was size with skill that came almost free and it was meant for lines 3-4. It was a player that had upside who had frustrated two organizations with his ethic and inability to get into shape. He rolled 7s in Edmonton and got it together and while I think you HAVE to give credit to the GM for getting the player, you also have to be realistic and understand that there was high levels of luck involved in how well this turned out.
Hall for Larsson: Oof. This was a bad trade when it happened, a bad trade all last year and it's a bad trade now. Nothing has really changed. He traded a superstar forward for a good defenseman. You can say all you want about Adam Larsson and you can say all you want about Taylor Hall: They don't make as many Taylor Halls as they do Adam Larssons.
Lucic: A risky, big contract to a player who needed to keep the offense coming. 6M per is not a big number but on an Oilers team that struggles with secondary scoring, cap space and team speed, it looks uglier right now than it should. If the Oilers can flush some roster wadding and get some speed and skill in, this will look better IMO.
The 2017 offseason: A f***ing unmitigated disaster with poor awareness, poor performance and a disgusting level of complacency. He literally made every wrong decision. It was clear the team had good injury luck and poor secondary scoring; doesn't improve depth and subtracts from secondary scoring. It was clear the team had three good defenseman; fails to add a roster defenseman at all. It was clear that bad contract negotiations would lead to cap crunch and the inability to address team depth: overpaid literally every player he signed except Zach Kassian. It's sort of hilarious that McDavid himself is the only reason it isn't worse. Like, he had to give himself a pay cut to make things work for the Oilers. Doing Chiarelli's job for him.
You could probably sum up Connor McDavid's tenure in Edmonton as "doing Peter Chiarelli's job for him", actually. He attracts all the players, outscores all the depth issues and even negotiates down his own damn contract.
