To have season tickets at UT comparable to mine at UNT around the 30 yard line, I would pay $640 a seat plus a $2500 donation annually. So, more than our exclusive club seating. Now I admit this is a bit of an apples and oranges situation, but it is still top level college football and a relative bargain. No one should be upset about these new prices for premium seating. Overall, this should lead to a full club. I don't use my seats but might buy these now that I do not need to big seat license so my parents who often use my tickets can get out of the heat/rain.
Now, I can see how someone could be upset after paying off an expensive seat license only have have the prices go up dramatically and the AD should try to address that issue with those customers. I think it depends on when you paid the license. A recent donor who is almost paid off or recently did so (as described above) has a strong gripe! If someone paid it 12 years ago, there is less discrepancy in the pricing over that long of a period.
EDIT: I would also add that another apples to oranges comparison is discussing professional sports. Although the donation is required for many levels of seating at UNT, it is still a donation to a student scholarship fund. Even the original stadium fund was to contribute to the AD budget, probably as part of debt repayment on the stadium (no info, just educated guess). And all for our university and not some random billionaire or corporation.