I was wondering if Miners are forced to fill full blocks or almost full block (according current block limit of 1MB) in bitcoin network (assuming that they all are honest enough to do so), what will be its effect on bitcoin network and transaction throughput? Which aspects I am missing on, that this change would be affecting? Even if miners are honest enough to do so, will it affect their profit? (In case of segwit, we can assume we are running older nodes.) Any comments will be helpful..

I am working on a research in bitcoin blockchain where I am making some hypothetical changes in policies of bitcoin blockchain. Due to this, it helps to increase the transaction throughput of bitcoin blockchain (or at least a thing I want to claim through my research). Or one can think of this research as an identical PoW blockchain to bitcoin, with some changes in its policies and structure. I am already working on a simulator called btcd - https://github.com/btcsuite/btcd. It is a full node implementation of bitcoin blockchain or what I understand of it. I was wondering how can I prove using btcd that transaction throughput have been increased through new policies. Other possible simulator names with suitable abstraction level will also be helpful. If we think of a scenario where it is absolutely necessary for miners to fill the blocks at its fullest (Apparently,  It will improve transaction throughput.), can this improvement be proved using any mathematical aspect?