comparing size wise F-35C to a F-16 is pointless.
compared to the upcoming J-20,Pak-Fa, and current Su-30,Su-33,J-15 it is small.
and i really mean it's internal weapons load will be small compared to current jets
In war, there are something called Battlefield Management. You need to understand this before you understand why F-35 is better than what it intended to replace, the 16s
When I just joined the Army, I was trained as a cavalry officer, the type of battle I took is a larger scale, with full platoon or even company assaulting a fixed position.
Now, let's look at this scenario.
I have a platoon of 45 men, with Trucks and Humvee , my objective is an rear C&C camp, and I know between me and my objective there are an enemy platoon between me. And for me to assault my objective, I will need to engage the enemy platoon, take them out, and then assault the C&C bunker.
Problem as far as I can see is, I pour all my platoon to engage the enemy platoon, chances are my own platoon would become combat ineffective just for that fight, that's more WIA and KIA than able person, and my objective is not to destroy the enemy platoon, but the C&C Bunker, and since my size is big, I can't sneak past the enemy platoon and that mean there is a chance I will not be able to even engage my objective, if my own platoon would be pinned down by the enemy patrol.
Now, if I have a team of 10 specially trained men, less guns and less equipment, but with 10 men, I can sneak past the enemy patrol by stealth and penetrate and engage the C&C bunker directly, once the jobs done, those 10 men would be sneaking out of the area again.
Now, when I use a smaller team but better "Quality" troop, at worse the worse case scenario is exactly the same with when I roll in with the whole platoon. Which is my 10 men squad were pinned down by the patrol and unable to assault the objective, so, literally, you are looking at less resources to manage the same objective.
Now, think about this scenario.
I have 8 F-16 and I need to bomb the enemy C&C bunker, now I know enemy fighter patrol the area leading up to the attack, with -35s, I can choose not to engage non-mission objective, because when you roll in with your -16, you will be forced to engage the enemy fighter when you were detected, but using stealth plane, you can choose what you want to engage, that effectively take out the numerical difference