Maybe bang the pan on the counter to flatten the batter before baking? I guess the main thing would be is how did it taste? You can always saw the bumpy parts off and eat them, then frost the rest! Who'll know?
Sounds like some experimenting is needed since both mixer and oven are new. Have fun!
I know your oven is new but it might be worth it to check the oven temp. It may run a bit hotter than you're used to your old one. I believe that the bulges and cracking are from cooking too quickly in a too hot oven. You may need to adjust the settings just a bit.
I don't why, but assume it's to prevent lumps and bumps, but I bang my cake pans on the counter and make sure the center is lower that the edges. That's how my mother-in-law insisted she baked her cakes for her son so I've followed the rules.
I agree that you should check your oven temp with another thermometer.