You can't really compare TW and HOI on even terms. TW is a tactical battle engine with just enough strategic level design to set up the tactical battles. HOI is a strategic game which uses a simplistic tactical screen to resolve encounters. In TW, you move blocks of something like 30-120 men, with each man represented as a unique element to deliver and suffer damage. In HOI, you move blocks of something like 3000 to 15000 men, with the brigades (larger than most of the armies in TW) that form it represented with individual stats for dealing and receiving damage. HOI is far more focused on the economic, logistic, and diplomatic aspects of warfare than TW. TW shines as a "battle generator" for pushing small groups of digital "warriors" around the field of battle. HOI, and HOI3 in particular, is a lot harder to learn, but will teach you a lot more about history and what wins and loses wars, not battles.