I legit always forget that TCU was an addition, feels like they always belonged in the big 12. Very good point
I see where you are coming from with Big Ten though...
Nebraska: Worst of all time before Big Ten, worst of all time still
Maryland: Probably got worse even though they were good in ACC golden era
Penn St: Rarely a factor before or after B10
Rutgers: Rarely a factor and had some horrific seasons after joining Big Ten before getting decent past few years, also major scandals
Penn St for football is possibly the greatest conference move of all time from a business/competition standpoint (maybe until OU/Texas to SEC), but for basketball and the rest of football those additions have really done nothing for Big Ten competition wise.