The issue with dubas is kinda two fold...
1. In a vacuum most of the moves he and made make sense on paper.
2. The current coach does not have the ability to adjust to the line up he's given to maximize the players he has.
Karlsson - shocking awful power play could legitimately have cost the pens enough pts in the standings to keep them out of the playoffs? Add one of the most prolific pp producers of the last ten years while also dumping most of the previous gms acquisitions.
Graves - at the time a second pairing defender who plays a two way game was needed to pair with petts, prior to coming to the pens graves was that guy. He was a career plus 90 or something, scored at a reasonable clip for his role, and could step into the power play when needed.
But you don't go out and get both graves and ek! This forces graves to play a style that, while he has the build for it, he doesn't play. He's not dumo, and he's never going to be dumo. It's Sullivan trying to rebuild a players game at what, age 27? Of course he's going to struggle. And while he's trying to "fix" graves he's also trying to change karlsson as well.
Both players have had significant regression since joint the penguins, that's coaching.
Grz - I assumed that he would be fighting for the number 6 role, getting limited minutes until Pickering, shea, or st ivany stepped up. Not only has he gotten significant minutes gifted to him when his play has not deserved it, graves (who has been a better player than him most nights) get scratched for multiple games after a single bad night. It's obvious to anyone that Grz sucks but he continues to get significant usage, that's not on the gm, that's on Sullivan.
The team needed to get younger and faster, so dubas brings in some young players who can skate in poolparty at age 25, glass at age 25, shea at 26, beau at age 26 and resigned st ivany at 24. (At the time of their signings/trades) In a vacuum individually these are decent depth moves for the 3rd/4th lines and the 3rd pairing. But a combination of injury, under performance across the board/poor usage by the coach has made them bad signings. Beau has been the Grz of the top six, pool party has been inexplicably benched and scratched over minor mistakes even though some nights he's the ideal 3rd line wingers, Grz gets a sweater over shea or st.ivany ect.
Hayes - if you know you are trying to deal Eller, which apparently was the case going back to last season, Hayes makes sense. He's a replacement for Eller on the 3/4th line, he plays center and wing so there positional flexibility, he was only 31 at the time, and prior to going to st.louis he was a productive top 9 player who was good on the power play. Plus st.louis paid to dump him with Philly is eating half his salary. He comes here, has some injury issues, but when healthy he is stuck in the 4th line, gets like 8 minutes a night and I don't think has sniffed the power play even though a big bodied forward who has hands and can park his ass in front of the net is exactly what is needed.
As someone said a few weeks ago "we knew this team wasn't going to great, but it shouldn't be THIS bad", coaching is what takes a middling team that should be fighting for the last playoff spot and turns them into a 30th (31st?) place team. This team plays with no heart, puts in no effort, can't seem to execute the simplest facets of the game like clean line changes, and has a complete lack of structure. That's coaching.
My only MAJOR current gripes with dubas are,
Jarry's contract which given his inconsistencies was a mistake at the time, but, a mistake most gms would probably have made given that Sullivan backed Jarry at the time.
The defense, pick Graves OR EK, and use that extra money to get another Petterson. The Grz contact was too big for a guy that was a healthy scratch for Boston at the end of last year. He should have been at most a 1 mil contact given he was playing to salvage his NHL career. Tho that extra mil he's getting isn't making or breaking anything, it's Grz usage not his contract.