I think your expectations are a bit unrealistic. I'm not trying to sound harsh, but as @Queen6 laptops are a compromise. Take gaming laptops, they're probably the most powerful, but at the expense of heat, and battery life. Another example is Macs, where apple generally chooses to not spin the fans, so they're run rather hot.So just head to MS store, get a SB2 15" and try it for a month. If X1E's fan issue (alternating between dead silent and jet engine) is fixed, consider to get back to X1E?
I prefer 15" laptop but others love 13"
Check out bestbuy they offer lenovo products, and also Microsoft. I've owned Surface products and they're good in some ways, but I feel they're very expensive. I prefer a better value for my $$
By all means visit the store and try them out, but don't sweat the small stuff