Sorry of English.
"Total war warhammer" games currently are in desperate need of 2 things. From the technical point of view.
Heavy multi threading and appropriate API.
By the time game 3 is out, which is 2020 or 2021, 8 cores and 16 threads will be like a minimum for gaming machines. We have 12 and 16 cores today. In 2 years this will only escalate. And game 3, with combined map will have long life.
Right now game is very dependent on speed of 1 core. More cores helps at least at 4 to 6 or 8, but 1 core is always 100% loaded.
This is the answer for users who wonder why their new processor and ultra powerful graphics card still give then 10-20 fps in 40 vs 40 massive battles on ultra unit scale. It is hard CPU limit. 1 core limit.
Game engine needs total rework for very good multithreading. For like any amount of cores (32 is really easy to buy now, half-pro platforms.)
Second thing, may be even more important in some cases, - DX12 or Vulcan exclusive game. No more "windows 7" and DX11 in 2020-2021 gigantic strategy game. The most important things about these APIs are very good optimization for draw calls and possibility to handle huge amount of interactive objects on the field with good performance. And no other game needs this that much like a total war titles! And it is very obscurely, why this is not implemented when this limit total war games so much? Unit sizes and actual performance. No more than 2 vs 2 stacks battles in campaign because, again, mainly for performance reasons.
And this lag game, in ultra unit sizes, when graphics are on all extreme setting but still a card loaded for 35% maximum, and you still have 10-14 fps for 80 units fighting (at zoom in).
This is top technical importance. It is not about balance or atmosphere where you can have "different feelings". This is about tech side of a product of the company. And it must have good quality.
Owning a game with all DLCs is not that cheap now, and customers expect great tech quality. And, at least future game 3, with a new or really modernized engine with much-needed new APIs exclusivity.
These things alone will totally cut the dreaded "end turn times" too. And personally I am totally fine with them, but many other players do not. And that opens a possibility for real all world map fog game 3 "mortal empires". With all continents in full scale. Not shrink and cut for better turn times.
It is easy - tech limitations limit game. And this limit the players impressions and emotions from these impressions.
And from the game perspective, easy and achievable short campaign victory, realistically by turn 50, will make impressions and gameplay not overwhelming, by the size of the map, for players. (Take 2 to 4 key provinces, may be far and strong, like Altdorf for orcs, but not 10. And destroy 2-3 factions. Period.) But this is all second. Engine is a tech base of the game. Good, new API engine - great possibilities!