I agree with the above posts that recommend that you thoroughly research the math departments in the universities where you apply to transfer. Let’s face it, if you hate St. Louis, who’s to say you wouldn’t hate Houston? If WashU is too homogeneous, maybe Notre Dame will be too Catholic or too midwestern? If the morale is low at WashU, maybe the morale is even lower at grey/isolated/grade-deflated Cornell? You may be trading one less than positive environment for an even worse situation. At least if the math department lets you be the ‘thinkers’ in the field, as you suggest, you’ll have improved your situation if you transfer.