Anyone with Black Ops II or newer can try Black Ops III for free!
Anyone with Black Ops II or newer can try Black Ops III for free!
The Beta will focus solely on multiplayer, with a full campaign planned once the game is released. The Black Ops series typically offers a solid campaign. BO 1 performed well, and BO 2 is currently strong (though I haven't completed it yet). I don’t see a major issue with a publisher releasing a single-player game at full price, provided the content, maps, modes, layouts, weapons, etc., are sufficient. The main concern arises when they release an MP-only title with features comparable to a previous game that included SP.
It looks like you're noticing how many games in a series feel very similar to what came before. You're questioning why CoD isn't always fresh each year, suggesting you're too close-minded. The exosuit in AW is a big deal, but overall, you're feeling frustrated about the lack of genuine change and the tendency to only focus on what criticizes.
Similar concepts exist, but reskins are a different matter. I haven't mentioned Crysis or Battlefield much in my posts, nor have I expressed a preference for them over other options. Suggesting a franchise without reskins would be Wolfenstein. Doom (the second version, which had more levels than the first) and Quake are worth mentioning. The Elder Scrolls aren't something I particularly enjoy.
In short, Morrowind and Oblivion both ran on the same engine (GameByro). It wasn’t until Skyrim that they moved to a different one (Creation). Overall, none of the games in the series used the exact same engine, though each saw graphical enhancements beyond just new skins. Running the same engine doesn’t mean a game is just a reskin.