While I don't disagree that some people would be very upset if Lip got in over their picks, the Smash crews have had a history of adding at least one "Where the heck did that come from?" character into every game since Melee. Yes, some particularly salty people would probably throw fits, but I think most would begrudgingly accept it if Lip (or any other obscure character) made it in.
How good/bad the reaction would be would also depend on how the character is announced. A solo reveal like Isabelle's would send people into a rage if it were something clearly planned like a Direct, but if they just randomly dropped the character trailer by itself or announced the character alongside another that people are excited for, the excitement would probably neutralize most of the negative reactions.
How good/bad the reaction would be would also depend on how the character is announced. A solo reveal like Isabelle's would send people into a rage if it were something clearly planned like a Direct, but if they just randomly dropped the character trailer by itself or announced the character alongside another that people are excited for, the excitement would probably neutralize most of the negative reactions.