Ford said that we could have any color car we wanted, as long as that color was black! Just like in every aspect of life (relationships, investments, whatever), there is a give-and-take necessary (in this case, compromise between manufacturer and consumer) to achieve maximum ROI.
Market forces will eventually prevail. People won't buy EVs if they aren't compatible with the charging system. Do you think the auto industry would have grown like it had if "gasoline" hadn't been standardized? So it's in the car makers best interest to "universalize" their designs as much as possible for maximum manufacturing efficiencies, maximum sales potential and maximum profit. This is called "Optimization"- finding the right mix of inputs that allow for maximum benefit to everyone in the loop.
I’m guessing a big part of the bp initiative is to standardize both the "vehicle side" and "dock side" connections. Similar to USB, connections will be cross-platform regardless of vehicle make/model. In other words, regardless of battery design, the important thing is for the connectors to be universal. I'm sure bp probably has a business unit specifically set up for producing, selling and distributing these components to car makers such that, regardless of the battery design, the vehicle can utilize the charging system.
As for the battery exchange program, yes, this poses specific design concerns in terms of "fit". But regardless, not everyone will want to subscribe to battery exchange (just like some people still don't subscribe to text messaging). In other words, if I don't have a car with the type of battery used in the system, I won't want to pay for that service. But you better believe I want my vehicle to have the right plug-in.
However, there is always a solution. Just like each vehicle became standardized on gasoline, maybe the one thing about ALL electric vehicles is that the same battery pack dimensions have to be standardized. Imagine the incredible economies of scale and production efficiencies that can be achieved if this were the case! Something like, "This is the battery, now build the car around it! You can do anything you want in terms of car design, but this is the size and shape of the power cell."
Or how about this; have you seen the adapters that allow a AA cell to be put in place of a C cell? It's basically a C cell size casing that houses an AA cell such that the AA properly fits in the space where a C cell would normally be. Since both the AA and C are 1.5V, they both work (of course, the AA probably won't last as long). So, maybe it’s simply the battery compartments on every EV that needs to be standardized, in terms of size, location and access, in order to make automated swapping a reality.
Here's something else to consider; maybe battery exchanges shouldn’t be automated. Oregon and NJ fuel stations don't allow self-service, and are actually required by law to have full-service attendants pumping the fuel. I don't know the reason for NJ's law, but in Oregon, the law was enacted to create jobs in order to counteract the decline in jobs caused by the implosion of the timber industry as it literally grew too large to be sustainable.
Maybe the "law" might have to be that EV battery swaps are performed by service station technicians. These EV technicians would do the work necessary to keep the charging/swap station operating and functioning properly. This could be one of the very specialized, high-tech/green-tech jobs created by the industry! NEW BUSINESS OPPORTUNITIES AND CAREER PATHS FOR AMERICA’S CLEAN ENERGY FUTURE!