M-Blow is a good skill, I take it on other teams, often as first skill. I just think there are other skills that will work better for this team. In particular, I think the Yeomen need Guard, Tackle first, and my first doubles pick for the other players is Guard, not M-Blow. So if I took M-Blow, it would be a long time before the team gets any, and only in small quantity. Wrestle + M-Blow is sub-optimal (whereas Wrestle + Guard works fine in practice). And I have prioritised defensive and positional skills (Dodge, Sidestep, S-Firm, Grab).
Partly it is a matter of playing style. Some coaches like to blitz every turn with a hunter-killer. I don't, I find this "habit-ridden and systematic". For me, the priority for Brets on defense has to be to attack the ball (especially against a killy team, which will likely take out 1 or 2 Peasants on the LoS).
I am planning to build a crowdsurfer, though (Blitzer with: Dodge, Frenzy, Sidestep). That will help with numbers (as well as keeping opponents honest).
Partly I am planning by analogy with the ST3 Elven teams, which excel once they have (say) 4 x Guard (but I don't recall ever having had M-Blow on such teams). I am hoping to get 6 or more Guarders on the team...

My arguments against D-Player are in a similar vein. Of course only time will tell.
All the best.