Marth, IIRC, was considered Upper Mid, as are Roy and Leif. (Lyn too, before the "tier list debaters" and efficiency whores started massively underrating her.) And yet, they're liked. So I wouldn't necessarily say that "the lower X FE character is on tier lists, the less they are liked".
its not that. I'm saying the higher they are on the tier list the less likely they are to be disliked. Those in high/god tier will hardly ever get any hate whatsoever and may achieve memetic badass status, while those under criticsm for thier gameplay will often also get hit with any personality disagreements to pour salt into the wound.
There are exceptions to the rule but generally it holds true, especialy in this game.