I wouldn't call these A-List defensemen yet. These are good, young, up and coming defensemen that signed these deals after their first entry level deal. They may get to A-List in a few years, not all of them will. The exact same position Myers was in when he signed his deal.
A-List D-men right now are people like Doughty ($7M), Weber ($7.8M), Keith ($5.5M - which is a steal), Subban ($9M)
Enstrom is probably overpaid for what he is now, but his contract can't even compared to these guys because of all of the RFA years that were bought in those contracts. Enstrom had mostly or all UFA years in his.
Myers may be a problem if / when the Jets become a cap team. Until then it doesn't matter. A $2.6M salary for Stuart for this year and next is peanuts and is splitting hairs to complain about.
Both Stuart and Enstrom come off the books after next year, so those contracts are not hurting the team at all.
Other then Trouba, the only contracts they need to figure out before both of these guys come off the books are Stafford (won't re-sign will free up more space), Burmi (still RFA signed for low or traded, Thorubrn - won't be re-signed, Tanev - 3rd / 4th line RFA, Postma - UFA, Chiarot - RFA won't command a big salary, Helleybuck - RFA who Atomic has decreed as AHL calibre so he will sign for peanuts as well).
There are things to fix on this team for sure, but these contracts are not an issue at all.