Pejorative phrases like "bush league" or weasel words perpetuate stereotypes which is the opposite of the objective of this thread. There are many clearer and more precise ways of expressing your sentiments.
Sorry, I didn't invent the term. Dictionary.com defines bush leaguer to mean a player who performs at an inferior level or an inferior manner. Marchand performs in an inferior manner by being a danger to other players. It originally could mean simply a minor-leaguer as well, but I don't think anyone really uses the term that way any more. (thefreedicionary.com doesn't even include that as a definition - only the "inferior" sense.) In the way it's used now (and it's a well-known phrase, like it or not), it means amateurish, or unprofessional.
Basically what I'm saying is that the definition you're using of a bush-league player is an archaic one. And certainly not the only one. Francis Bouillon was not a bush-league player in the common sense of the term. Case in point, google bush league and Bouillon - the only hits are talking about bush league play in the sense that I mean it, with nothing referring the Bouillon in the sense that you mean it.
As for nicknames from the past, I think we all know that names they applied back then would sometimes not be seen as appropriate now. Words change in meaning an acceptability, you know, as we saw from the Kraut Line discussion. There are a number of baseball players in history who were called "Nig", for instance, and for the very reason it would be seen as offensive now. We'd never use that as a nickname now.
Of course bush league is a derisive term, it's used to deride something seen worthy of derision. Brad Marchand's play is worthy of derision; that doesn't mean all minor-league players are, and I didn't apply the term indiscriminantly, or in the archaic sense.