I thought it was well done in seasons 2 and 3, he was introduced as a stand up guy, who wasn’t afraid to stick with the things he loved just because he might face some bullying or harassment over it, he showed he accepted people for who they were regardless, and that he only judged people if they were assholes. Moving into season 3 he stuck with those established character traits, while also developing and becoming a bit more interesting, with having to do whatever it took to help his family out given their unfortunate financial situation, coming back to McKinley after his absence, his attempts to rekindle his relationship with Mercedes - I thought his character was really well handled in both seasons, and he was a real bright spot, as far as the characters of the show are concerned.
Then season 4 happened and that all went down the crapper - The writers changed his character so drastically and dumbed him down to such a point that you started to really get irritated, wondering why they didn’t just create a newbie character with those traits. And the whole point of this character regression and sabotage? So that he could…become the male-Brittany…so that in turn he could date her. Yep.
Well I guess the trade off paid off though, right? I mean, we lost the nice guy, with the interesting character development, who often provided a sweetness to offset a lot of the other character’s unpleasant bitterness, so that we could have…an unengaging, mostly disliked and rejected pairing that didn’t last a season, and which was dumped by season 5. And also Blam. Yay.