$10 data fee is just for when you upgrade to a new smartphone, first off.
They should have sent you something in the mail to find out if you qualify for gold or not. (I just looked. Looks like the 1500-minute plan would be Silver and the 3000-minute plan would be Gold. (I believe lines beyond the first two are considered add-ons.))
There are good things and bad things about Sprint. It may work for you, it may not. I happen to love their plans
for me. I don't think they necessarily have the best family plans. I can't speak for your employee discount; there might have been good reasons for the change. I know that I have two lines, and my friend has the second. (I have two separate plans on my account.) She has an employee discount, and it only applies to her line and her plan. As far as yours goes, well, it makes the bill $4 more a month. So, lump sum, it's close to $50 more a year you're giving them. Is it what you want? No, but it's not huge in the grand scheme of things either. It's a latte or a Happy Meal a month. Or a pack of Oreos...
What do I think? I think that all phone companies are out to make a profit, they're all of them equally likely to screw you over, and it's not worth getting upset over. In my opinion, the only reason to get upset is if you're cordial and you're treated like crap by a live human being. The difference between companies is how they screw you over and which way you mind the least. With this outlook, I am rarely dissatisfied and often happily surprised.