Mentors are incredibly important to success in most aspects of life. Someone to support you and show you how. Inventing the wheel on your own is less efficient and often results in failure. Having someone to show you how, to teach you what has already been learned before you, is the most critical aspect of how society, people, and yes, hockey players achieve a new level of success.
The most concerning aspect of this management group so far, is an alarming imbalance in the strategy so far.
Having mentors is important, in that you're correct. They have some mentors for the team in guys like Tuch, Okposo, Girgensons, Skinner, and Anderson. Also having a veteran Dman would have been nice. Lyubushkin was a solid addition, but has had limited time in the NHL so far and wasn't a vet they could count on to mentor the younger guys so there was definitely room to add there.
What they don't or didn't have was a ton of roster space to add 4 or 5 vets to the team, not without sacrificing development time for Quinn, Peterka, Krebs, Power and to an extent Cozens. While many fans made up their mind on some of the players last offseason, management clearly had not. They seemed to still be evaluating and trying to develop Mittelstadt, Joker, Bryson and to a lesser extent Asplund and Fitzgerald. Obviously Asplund and Fitz are gone, Bryson has regressed and Joker seems to be what he is at this point.
This team is not going to make noise in the playoffs without the development of Cozens, Quinn, Power, or several others. In order for them to develop, they need to play. You can look at many teams developing young players and they surround them with vets, but most of those teams are only developing 1 or 2 young players in the NHL at a time, not 5 or 6 of them like the Sabres are. Add to that the need to possibly find roster spots for Savoie, Ostlund, Kulich, Rosen or several others in the next couple of seasons and the need to develop them now or move on from them is even greater.