Let's see here...
Ike: Because he's strong and fast. He's a balanced out swordsman who has the strength on par of cavaliers and the speed on par to Myrmidons...although they are still considered the fastest units besides Bird tribe Laguz (Who are arguably faster than anything alive). People consider him broken, but I'd say that he's fairly balanced if you go by average stats. Plus, not too many Lords besides Sigurd in FE games are High Tier like Ike is (Despite me not giving a crap about tiers XD )
I would have chose Mia as a second favorite, but I like her more in FE10. So I'll just give an honorable mention to Ilyana.