I think part of it is just different players have different expectations and/or look at things differently.
For some people every new game has to be a revolution with a new engine, every new DLC must break new ground that has never been touched by developer or modder before. For others, we're happy to play games that we enjoy, even if they may be similar to other games we also enjoy, (and same goes for DLC. Some, like me, also just prefer paying for the developers idea of what a faction should be, than playing a modders idea of what they should be for free.)
For some DLC is a dirty word, and no matter how good it is they will feel it is wrong. For others, we take each DLC as it comes, and judge them on their own merit and price.
Then there are some people who will never be happy whatever CA does. And then there's the thankfully very, very small minority who just like causing trouble and may not even really be interested in the game, just in the "fun" they get from winding others up.
Those are just some of the different points of view I've seen across various Total War boards in my many years of playing Total War and being part of the community (either passively as a lurker or actively as, well, Welsh Dragon. ) And each likely has merits (well, except for the causing trouble for troubles sake one,) and those that hold that view likely have good reasons for them to hold those views.
Personally, I've enjoyed every Total War I've played. (Which is everything from Medieval 1 to Rome 2, including all expansions and DLC except Blood & Gore types.* I think CA gets more right than they do wrong, and don't have an issue with DLC as long as both it and the game it is for a reasonably priced for the content. But I respect not everyone feels that way.
(*Unfortunately Attila and Warhammer I have issues with them triggering my light sensitivity and migraines, though still hope to play them some day if I can find a solution.)
I the end, I think Total War: Sagas aren't going to appeal to everyone, much like Warhammer doesn't, or firearms era or the Shogun games etc. But I think that they have the potential to be a lot of fun, to cover specific periods or events that might never make it into a Major Total War release (American Civil War is to me a very good candidate for a Saga game) and also to bridge the gap between Major releases.
I saw a post earlier, can't remember where, that I think described the situation best. To paraphrase.
There are now 3 types of Historical: Total War game.
1. Eras. The Major releases, covering great sweeps of history. Medieval, Empire, Rome.
2. Characters. Standalone games/expansions built off the work done for a Major, but based around a person in a smaller timeframe. Napoleon, Attila.
3. Sagas. Standalone games/expansions built off the work done for a Major, but based around a specific event in a smaller timeframe. Mongol Invasion, Fall of the Samurai
Some will say it's just a rebranding, and in part yes it is. CA staff have even highlighted that a Saga game isn't a new idea, more them putting a name to something they have done in the past. But having clearly defined names for each type of game is I think a good idea, as it will hopefully lead to people having more realistic expectations when it comes to each game, be it Era, Character or Saga.
As for 64 Bit, I get the impression the first Era game will be built off Rome 2/Attila, so probably not 64 bit. But future titles, I'd say there's a reasonable chance, especially moving forward from the next Eras game.
All the Best,
Welsh Dragon.