Eason was a decent QB. And he certainly played well enough to do his part in the 85 SB run (as a WC, all 3 on three on the road). He did have one knock and that is his NFL draft class produced a bunch of successful NFL QBs. Eason was in the shadow of others, even drafted later, that out performed him.
In today's NFL Eason would have a much better shot at being a notable QB. QBs are given FAR more protection than the days of Grogan/Eason (and the receivers they threw too could be almost murdered by safeties/LBs). Younger people who did not see the previous NFL era would probably be shocked to see the walloping the QB and his receivers legally would get. IMHO Eason had the extremely understandable affliction of not wanting to be severely hurt. When the wrecking crew was rushing at him he would sometimes be affected by it. And for those who weren't watching the NFL in 85, the very definition of the post SB era wrecking crew was the 85 Bears defense. Leading up to the SB the bears had made mincemeat of good teams (Parcells Giants and I think the Montana 49ers). Think about this, not counting a last minute garbage time score in the SB, over 12 quarters of playoff football the Bears gaveup one single field goal. That's it! One single field goal in 12 quarters of playoff -- and btw that FG was because they turn the ball over inside their own 20). Wow. With due respect to one of the Ravens' defenses, the Bears D was friggin frightening. Think our running was deficient against Denver? I believe we had 1 yard of rushing against the Bears in the SB (it might have even been negative 1, can't remember exactly. Also if I recall one of our starting RBs was another guy afflicted with fear of injury from the Bears). These guys were so good I think Ryan got down to one defensive play call: 6 guys go at and assault the QB and everyone else just find someone to cover. And if it was a handoff/run just assault the RB on the way to assaulting the QB (an exaggeration of course).
As the SB game got toward the end of the first quarter, like every other team the Patriots OL could not contain the Bears rush/domination of the trench. Eason was shaken by the assault. Completely understandable, I'd bet everyone posting here would have been too. The lone exception to that understandable human need for staying healthy is NFL QB (or maybe a boxer) (Grogan was fearless though. He stood in and took the punishment even as there was quickly no hope for the Patriots to win).
I'll say this though. Eason, if I recall, put the ball right on the money in Morgan's hands for a TD. Patriots could have been up 7 to 0 and had a Rocky 4 moment (you cut him, he's bleeding. You see he's not a machine, he is a man). No doubt in my mind the Bears would have a temporary chink in their armor. And if it had been Grogan instead of Eason starting (Oh Berry!), Morgan holds onto that catch, and we could have scrathced out a FG on the next drive?? We may have only lost 35 to 10 -- seriously it could have given the Patriots a chance to at least make the game competitive into the 4th quarter.